TW202030829A - Integration of microdevices into system substrate - Google Patents

Abstract

In a micro-device integration process, a donor substrate is provided on which to conduct the initial manufacturing and pixelation steps to define the micro devices, including functional, e.g. light emitting layers, sandwiched between top and bottom conductive layers. The micro-devices are then transferred to a system substrate for finalizing and electronic control integration. The transfer may be facilitated by various means, including providing a continuous light emitting functional layer, breakable anchors on the donor substrates, temporary intermediate substrates enabling a thermal transfer technique, or temporary intermediate substrates with a breakable substrate bonding layer.

Description

Integrate the micro device in the system substrate

The present invention relates to optoelectronic microdevices, and more specifically, it relates to integrating optoelectronic microdevices into a system substrate with enhanced bonding and conductivity capabilities.

The purpose of the present invention is to overcome the shortcomings of the prior art by providing a system and method for transferring a micro device from a donor substrate to a system substrate.

According to an embodiment of the present invention, a method of manufacturing a pixelated structure includes: providing a donor substrate; depositing a first conductive layer on the donor substrate; depositing a fully or partially continuous light-emitting function layer on the first conductive layer Depositing a second conductive layer on the functional layer; patterning the second conductive layer to form a pixelated structure; providing bonding contacts for each pixelated structure; fixing the bonding contacts to the system substrate; and Remove the donor substrate.

In one embodiment, continuous pixelation is used to turn the microdevice into an array.

In another embodiment, the device is separated and transferred to the intermediate substrate by filling the vacancies between the micro devices.

In another embodiment, the microdevice is post-processed after transferring to the intermediate substrate.

According to an embodiment, a bonding structure may be provided. The bonding structure may include a plurality of microdevices on the donor substrate, wherein each microdevice includes one or more conductive pads formed on the surface of the microdevice; and the temporary material covers each microdevice or the one or more At least a part of the conductive pad. In one case, the temporary material acts as an anchor, which holds the plurality of microdevices inside the housing structure in the donor substrate.

According to one embodiment, a method for integrating a micro device on a backplane may be provided, the method includes: providing a micro device substrate composed of one or more micro devices; connecting the pads on the micro device and the corresponding Pads to bond a group of selective microdevices from the substrate to the backplate; and to separate the microdevice substrate to leave the bonded selected group of microdevices on the backplate.

Cross references to related applications

This application is a partial continuation of the U.S. Application No. 15/820,683 filed on November 22, 2017 and claims its priority. The U.S. Application No. 15/820,683 claims the priority and rights of the following applications: U.S. Provisional Patent Application No. 62/426,353 filed on November 25, 2016, U.S. Provisional Patent Application No. 62/473,671 filed on March 20, 2017, U.S. Provisional Patent Application filed on April 7, 2017 Case No. 62/482,899 and U.S. Provisional Patent Application No. 62/515,185 filed on June 5, 2017, and Canadian Patent Application No. 2,984,214 filed on October 30, 2017. Each of these applications One is incorporated herein by reference in its entirety.

This application also claims the rights and interests of U.S. Provisional Patent Application No. 62/734,679 filed on September 21, 2018 and U.S. Provisional Patent Application No. 62/809,161 filed on February 22, 2019. These provisional patent applications The case is incorporated into this article by reference in its entirety.

This application further claims the rights and interests of U.S. Provisional Patent Application No. 62/746,300 filed on October 16, 2018, which is incorporated herein by reference in its entirety.

Although the teaching of the present invention is described in combination with various embodiments and examples, the teaching of the present invention is not intended to be limited to these embodiments. On the contrary, the teachings of the present invention cover various alternatives and equivalents, as those skilled in the art will understand.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by ordinary skilled persons of the present invention.

As used in this specification and the scope of the patent application, unless the context clearly dictates otherwise, the singular forms "a/an" and "the" include multiple referents.

In this manual, the terms "device", "vertical device" and "microdevice" are used interchangeably. However, those skilled in the art should understand that the embodiment described here has nothing to do with the size of the device.

In this specification, the terms "donor substrate" and "temporary substrate" are used interchangeably.

In this specification, the terms "receptor substrate", "system substrate" and "backplane" are used interchangeably.

Examples of optoelectronic devices are sensors and light emitting devices, such as light emitting diodes (LEDs).

The present invention relates to a micro-device array display device, wherein the micro-device array can be bonded to the back plate by a reliable method. The micro device can be fabricated on top of the micro device substrate. The micro device substrate may include micro LEDs, inorganic LEDs, organic LEDs, sensors, solid state devices, integrated circuits, micro-electromechanical systems (MEMS), and/or other electronic components.

LEDs and LED arrays can be classified as vertical solid-state devices. The micro device can be a sensor, LED, or any other solid device grown, deposited or monolithically fabricated on a substrate. The substrate may be an inherent substrate or acceptor substrate of the device layer to which the device layer or the solid-state device is transferred.

The acceptor substrate can be any substrate, and can be rigid or flexible. The acceptor substrate may include, but is not limited to, a printed circuit board, a thin film transistor (TFT) backplane, an integrated circuit substrate, or in the case of optical microdevices such as LEDs, such as driving circuit backplanes and other display components. The patterning of the micro-devices on the device donor and acceptor substrates can be different from transfer technologies with different mechanisms such as pick-and-place (for example, electrostatic transfer heads, elastomer transfer heads) or direct transfer mechanisms (for example, dual-function pads) Used in combination.

In the present invention, the contact pad in the acceptor substrate refers to a designated area in the acceptor substrate to which the micro device is transferred. The contact pad may include a bonding material that permanently holds the microdevice. The contact pads can be stacked in multiple layers to provide a mechanically stable structure with improved bonding and conductivity.

The system substrate can be made of glass, silicon, plastic or any other common materials. The system substrate may also have active electronic components, such as (but not limited to) transistors, resistors, capacitors, or any other electronic components commonly used in system substrates. In some cases, the system substrate may be a substrate with electrical signal columns and rows. The system substrate may be a backplane with a circuit for deriving the micro LED device.

1A shows an embodiment of a donor substrate 110 with a lateral functional structure including a bottom planar or sheet-shaped conductive layer 112; a functional layer 114, such as a light emitting quantum well; and a top pixelated conductive layer 116. The conductive layers 112 and 116 may be formed of doped semiconductor materials or other suitable types of conductive layers. The top conductive layer 116 may include several different layers. In one embodiment, as shown in FIG. 1B, a current distribution layer 118 is deposited on top of the conductive layer 116. The current distribution layer 118 can be patterned. In one embodiment, the patterning can be performed by lift off. In another case, patterning can be performed by photolithography. In an embodiment, the dielectric layer may be deposited and patterned first and then used as a hard mask to pattern the current distribution layer 118. After the current distribution layer 118 is patterned, the top conductive layer 116 may also be patterned to form a pixel structure. After patterning the current distribution layer 118 and/or the conductive layer 116, a final dielectric layer 120 may be deposited on and between the patterned conductive layer 116 and the current distribution layer 118, as shown in FIG. 1C. The dielectric layer 120 can also be patterned to create an opening 130 as shown in FIG. 1D to provide a path to the current distribution layer 118. An additional leveling layer 128 may also be provided to level the upper surface, as shown in FIG. 1E.

As shown in FIG. 1E, a pad 132 is deposited in each opening 130 on top of the current distribution layer 118. The resulting structure with pads 132 is bonded to the system substrate 150 with pads 154, as shown in FIG. 1F. The pads 154 in the system substrate 150 can be separated by the dielectric layer 156. There may be other layers 152 between the system substrate pad 154 and the system substrate 150, such as circuitry, planarization layers, and conductive traces. The system substrate pad 154 may be bonded to the pad 132 by fusion bonding, anodic bonding, thermal compression bonding, eutectic bonding, or adhesive bonding. One or more other layers may also be deposited between the system device and the lateral device.

As shown in FIG. 1G, the donor substrate 110 can be removed from the lateral functional device, such as the conductive layer 112. The conductive layer 112 may be thinned and/or partially or completely patterned. The reflective layer or black matrix 170 can be deposited and patterned to cover the area between the pixels on the conductive layer 112. After this stage, other layers can be deposited and patterned according to the function of the device. For example, a color conversion layer may be deposited to adjust the color of the light generated by the lateral devices and pixels in the system substrate 150. It is also possible to deposit one or more color filters before and/or after the color conversion layer. The dielectric layer in these devices, for example, the dielectric layer 120 may be an organic substance such as polyamide or an inorganic substance such as SiN, SiO ₂ , Al ₂ O ₃ or the like. Different processes can be used for this deposition, such as plasma enhanced chemical vapor deposition (PECVD), atomic layer deposition (ALD) and other methods. Each layer can be one deposition material or a combination of different materials deposited separately or together. The bonding material may be deposited only as a part of the pad 132 of the donor substrate 110 or the pad 154 of the system substrate. For some of the layers, there may also be some annealing process. For example, the current distribution layer 118 may be annealed according to the material. In one example, the current distribution layer 118 may be annealed at 500° C. for 10 minutes. Annealing can also be performed after different steps.

2A shows an exemplary embodiment of a donor substrate 210 having a lateral functional structure including a first top planar or sheet-shaped conductive layer 212; a functional layer 214, such as a light-emitting layer; and a second bottom pixelated conductive layer Layer 216; current distribution layer 218; and/or bonding pad layer 232. Figure 2B shows all or one of the patterned layers 216, 218, 232 to form a pixel structure. The conductive layers 212 and 216 may be composed of multiple layers including highly doped semiconductor layers. Some layers 228, such as a dielectric, may be used between the patterned layers 216, 218, and 232 to flatten the upper surface of the lateral functional structure, as shown in FIG. 2C. The layer 228 may also have other functions, such as a black matrix. The resulting structure with pads 232 is bonded to the system substrate 250 with substrate pads 254, as shown in FIG. 2D. The pads 254 in the system substrate can also be separated by the dielectric layer 256. There may be other layers 252 between the system substrate pad 254 and the system substrate 250, such as circuitry, planarization layers, and conductive traces. The bonding can be performed, for example, by fusion bonding, anodic bonding, thermocompression bonding, eutectic bonding, or adhesive bonding. Other layers can also be deposited between the system device and the lateral device.

The donor substrate 210 can be removed from the lateral function device. The conductive layer 212 may be thinned and/or patterned. The reflective layer or black matrix 270 may be deposited and patterned to cover the area between the pixels on the conductive layer 212. After this stage, other layers can be deposited and patterned according to the function of the device. For example, a color conversion layer may be deposited to adjust the color of the light generated by the lateral devices and pixels in the system substrate 250. It is also possible to deposit one or more color filters before and/or after the color conversion layer. The dielectric layers in these devices, such as 228 and 256, can be organic materials such as polyamide or inorganic materials such as SiN, SiO ₂ , and Al ₂ O ₃ . Different processes can be used for this deposition, such as PECVD, ALD and other methods. Each layer can be one deposition material or a combination of different materials deposited separately or together. The material of the bonding pad 232 may be deposited as a part of the pad 232 of the donor substrate 210 or the pad 254 of the system substrate. For some of the layers, there may also be some annealing process. For example, the current distribution layer 218 may be annealed according to the material. In an example, the current distribution layer may be annealed at 500°C for 10 minutes. Annealing can also be performed after different steps.

In another embodiment shown in FIG. 3A, a mesa structure is created on the donor substrate 310. The micro device structure is formed by etching through different layers, such as the first bottom conductive layer 312, the functional layer 314, and the second top conductive layer 316. The top contact 332 may be deposited on top of the top conductive layer 316 before or after etching. In another case, multilayer contacts 332 can be used. In this case, a part of the contact layer 332 may be deposited before etching, and a part of the contact layer may be deposited after etching. For example, an initial contact layer that generates an ohmic contact by annealing the conductive layer 316 may be deposited first. In one example, the initial contact layer may be gold or nickel. Other layers 372 such as dielectric or metal insulator structure (MIS) can also be used between mesa structures to isolate and/or insulate each structure. After forming the microdevice, a filler layer 374 such as polyamide can be deposited, as shown in FIG. 3B. If only selected microdevices are transferred to the cassette (temporary) substrate 376 during the next step, the filler layer 374 can be patterned. The filler layer 374 can also be deposited after the device is transferred to the temporary substrate. The filler layer 374 can serve as the housing of the micro device. If the filler layer 374 is used before the transfer, the peeling process may be more reliable.

The device is bonded to a temporary substrate (cassette) 376. For example, the bonding source may vary and may include one or more of the following: electrostatic bonding, electromagnetic bonding, adhesive bonding, Van-Der-Waals force bonding, or thermal bonding . For thermal bonding, a substrate bonding layer 378 having a melting temperature of T1 can be used. The bonding layer 378 may be conductive or may include a conductive layer and a bonding layer, and the bonding layer may be adhesive bonding, thermal bonding, or light-assisted bonding. The conductive layer can be used to bias the device on the substrate 376 to identify defects and characterize device performance. This structure can be used in other embodiments presented here. In order to solve some surface profile unevenness, pressure can be applied during the bonding process. The temporary substrate 376 or the donor substrate 310 can be removed and the device left on either. The process explained herein is based on leaving the device on the temporary substrate 376, however, when the device is left on the donor substrate 310, similar steps can be used. After that, additional processes can be performed on the micro device, such as thinning the device, creating a contact bonding layer 380 on the bottom conductive layer 312, or removing the filler layer 374. The device can be transferred to the system substrate 390, as shown in Figures 3D and 3E. Different techniques can be used for this transfer. In one case, thermal bonding is used for transfer. In this case, the melting point of the contact bonding layer 380 on the system substrate contact pad 382 is T2, where T2>T1. Here, a temperature higher than T2 will melt both the substrate bonding layer 378 and the contact bonding layer 380 on the pad 382.

In a subsequent step, the temperature drops to between T1 and T2. At this time, the device is bonded to the system substrate 390 through the contact bonding layer 380, so that the contact bonding layer 380 is solidified, but the substrate bonding layer 378 is melted. Therefore, moving the temporary substrate 376 leaves the microdevices on the system substrate 390, as shown in FIG. 3E. The process can be made selective by applying local heating to selected pads 382. Moreover, in addition to local heating, a global temperature can be used, for example, placing the substrates 376 and 390 in an oven and performing the process by increasing the overall atmosphere therein, thereby increasing the transfer speed. Here, the global temperature on the temporary substrate 376 or the system substrate 390 can make the temperature close to the melting point of the contact bonding layer 380, for example, between 5°C and 10°C lower than the melting point, and the local temperature can be used for melting and the selected device. Corresponding contact bonding layer 380 and substrate bonding layer 378. In another case, the temperature can be increased to be close to the melting point of the substrate bonding layer 378 (higher than the melting point of the contact bonding layer 378), for example, between 5°C and 10°C lower than the melting point, and the temperature after heating For the device in contact with the pad 382, the selected area of the substrate bonding layer 378 is melted by the temperature transfer performed by the device from the pad 382.

FIG. 3F shows an example of a thermal curve. The melting temperature Tr melts the contact bonding layer 380 and the substrate bonding layer 378, and the curing temperature Ts solidifies the contact bonding layer 380 with the bonding pad 382, and the substrate bonding layer 378 Still melting. The melting can be localized or can at least make the bonding layer soft enough to release the microdevice or activate the process of alloy formation. Here, other forces can also be used in combination or alone to hold the device on the bonding pad 382. In another case, the temperature profile can be generated by applying current through the device. Because the contact resistance will be high before bonding, the power dissipated on the bonding pad 382 and the device will be high, thereby melting the contact bonding layer 380 and the substrate bonding layer 378. As the bond is formed, the resistance will decrease and the power dissipation will also decrease, thereby lowering the local temperature. The voltage or current through the pad 382 can be used to indicate the quality of the bond and when to stop the process. The donor substrate 310 and the temporary substrate 376 may be the same or different. After the device is transferred to the system substrate 390, different process steps can be performed. These additional processing steps can be planarization, electrode deposition, color conversion deposition and patterning, color filter deposition and patterning, and so on.

In another embodiment, the temperature used to release the microdevices from the cassette substrate 376 increases as the alloy begins to form. In this case, when the bonding alloy is formed on the bonding pad 382 of the acceptor substrate 390 and the bonding layer is cured, the temperature can be kept constant, thereby keeping the micro device in place on the acceptor substrate 390 Place. At the same time, the bonding layer 378 on the cartridge 376 connected to the selected microdevice is still melted (or soft enough) to release the device. Here, a part of the material required to form an alloy may be on the micro device, and another part is deposited on the bonding pad 382.

In another embodiment, a filler layer 374 may be deposited on top of the box substrate 376 to form a polymer filler/bonding layer 374/378. Next, the microdevices from the donor substrate 310 can be pushed into the polymer filler/bonding layer 374/378. Then, the micro device can be separated from the donor substrate 310 selectively or as a whole. The polymer filler/bonding layer 374/378 can be cured before or after separating the microdevice from the donor substrate 310. The patternable polymer filler/bonding layer 374/378, especially if multiple different devices are integrated into the cassette substrate 376. In this case, the polymer filler/bonding layer 374/378 may be created for one type in which the microdevice is buried and separated from its donor 310. Next, another polymer filler/bonding layer 374/378 is deposited and patterned for the next type of microdevice. Then, the second microdevice can be buried in the associated layer 374/378. In all cases, the polymer filler/bonding layer 374/378 can cover some or all of the microdevices.

Another way to increase the temperature can be to use microwaves or lamps. Therefore, a layer can be deposited on each of: the bonding pad 382; a part of the pad 382; a micro device; or a part of the box 376 that absorbs microwaves or light and locally heats the micro device. Alternatively, the cassette 376 and/or the receptor substrate 390 may include heating elements that can selectively and/or globally heat the microdevice.

Other methods can also be used to separate the microdevice from the temporary substrate 376, such as chemical force, optical force, or mechanical force. In one example, the microdevice can be covered with a sacrificial layer, which can be debonded from the temporary substrate 376 by chemical, optical, thermal, or mechanical forces. The debonding process can be selective or global. The global debonding transfer to the system substrate 390 is selective. If the debonding process of the device and the temporary substrate (cassette) 376 is selective, the transfer force can be applied to the system substrate 390 selectively or globally.

The transfer process from the cassette 376 to the receptor substrate 390 can be based on different mechanisms. In one case, the cartridge 376 has a bonding material that releases the device in the presence of light, while the same light cures the bonding of the device to the receptor substrate.

In another embodiment, the temperature of the bonding layer 380 used to cure the device to the receptor substrate 390 causes the device to be released from the cartridge 376.

In another case, the current or voltage causes the bonding layer 380 of the device to the donor substrate 310 to cure. The same current or voltage can release the device from the box 376. Here, the release can be a function of the piezoelectric effect or temperature caused by the current.

In another method, after the bonding of the curing device to the receptor substrate 390, the device is pulled out of the cassette 376 after bonding. Here, the force to hold the device to the box 376 is less than the force to bond the device to the receptor substrate 390.

In another method, the box 376 has a via hole that can be used to push the device out of the box 376 into the receptor substrate 390. This pushing can be done in different ways, such as using a micro rod array or by pneumatic means. For pneumatic structures, disconnect the selected device. For micro rods, the selected device is moved toward the receptor substrate 390 by passing the micro rod through the associated via of the selected device. The microrods can have different temperatures to facilitate transfer. After the transfer of the selected device is completed, the micro-rod is retracted and the same rod is aligned with the vias of another set of micro-devices, or a set of vias aligned with the newly selected micro-device is used to transfer the new device.

In one embodiment, the box 376 can be stretched to increase the spacing between devices in the box 376 to increase throughput. For example, if the box 376 is 1 × 1 cm ² , where the device pitch is 5 microns, and the pixel pitch of the receiver substrate 390 (for example, a display) is 50 microns, the box 376 can fill 200 × 200 (40,000) pixels at a time . However, if the box 376 is stretched to 2 × 2 cm ² , and the device pitch is 10 microns, the box 376 can be filled with 400 × 400 (160,000) pixels at a time. In another case, the box 376 can be stretched such that at least two micro-devices on the box 376 become aligned with two corresponding positions in the receptor substrate. The stretching can be performed in one or more directions. The cassette substrate 376 may include or consist of a stretchable polymer. The micro device is also fixed in another layer or the same layer as the cassette substrate 376.

A combination of the methods described above can also be used to transfer the microdevice from the cassette 376 to the receptor substrate 390.

During the production of the cassette (temporary substrate) 376, the microdevice can be tested to identify different defects and device performance. In one embodiment, the device can be biased and tested before separating the top electrode. If the device is a transmitting device, a camera (or sensor) can be used to extract defects and device performance. If the device is a sensor, it can be stimulated to extract defects and performance. In another embodiment, the top electrodes 332 may be patterned into groups for testing before being patterned into individual devices. In another example, a temporary common electrode between more than one device is deposited or coupled to the device to extract device performance and/or extract defects.

The methods described above with respect to Figures 3A-3D-including but not limited to separation, formation of filler layers, different functions of filler layers, testing, and other structures-can be used for other structures including the structures described below.

The method discussed here for transferring the microdevice from the cartridge (temporary substrate) 376 to the receptor substrate 390 can be applied to all cartridge and receptor substrate configurations presented here.

The device on the donor substrate 310 can be produced with two contacts 332 and 380 on the same side opposite to the donor substrate 310. In this embodiment, the conductive layer on the box 376 can be patterned to independently bias the two contacts 332 and 380 of the device. In one case, the device can be directly transferred from the cassette substrate 376 to the acceptor substrate 390. Here, the contacts 332 and 380 may not be directly bonded to the receptor substrate 390, that is, the receptor substrate 390 does not need to have special pads. In this case, a conductive layer is deposited and patterned to connect the contacts 332 and 380 to appropriate connections in the receptor substrate 390. In another embodiment, the device may first be transferred from the cassette 376 to the temporary substrate before transferring to the acceptor substrate 390. Here, the contacts 332 and 380 may be directly bonded to the receptor substrate pad 382. The device can be tested in the cassette 376 or in a temporary substrate.

In another embodiment shown in FIG. 4A, the mesa structure as described above is produced on the donor substrate, in which different layers are etched through, such as the first bottom conductive layer 412; the functional layer 414, such as The light-emitting layer; and the second top conductive layer 416 are formed with a micro device structure. The top contact 432 may be deposited on top of the top conductive layer 416 before or after etching.

The temporary substrate 476 includes a plurality of grooves 476-2 initially filled with a filling material, for example, a soft material such as a polymer or a solid material such as SiO ₂ and SiN. The groove 476-2 is located under the surface and/or substrate bonding layer 478. The device is transferred to the temporary substrate 476 on top of the trench 476-2, and the device includes contact pads 432. Moreover, each microdevice may include other passivation layers and/or MIS layers 472 surrounding each microdevice for isolation and/or protection. The filling material 474 can be used to fill the space between the devices. After the device is post-processed, another lower contact pad 480 can be deposited on the opposite surface of the device. Before depositing the lower contact pad 480, the contact layer 412 may be thinned. Then, the filling material 474 can be removed, and the groove can be emptied by various suitable methods such as chemical etching or evaporation to cause or promote the release of the surface of the bonding layer 478 and/or selected sections. A process similar to that previously described above can be used to transfer the device to the system (receptor) substrate 490. In addition, in another embodiment, the force applied from the pad 432, such as pushing or pulling, may damage the surface above the evacuated groove 476-2 and/or the bonding layer 478 while maintaining the unselected mesa structure attachment To the temporary substrate. This force can also release the device from the temporary substrate 476, as shown in Figures 4B and 4C. The depth of groove 476-2 can be selected to manage some micro device height differences. For example, if the height difference is H, the depth of the groove may be greater than H.

The device on the substrate 310 can be produced to have two contacts 432 and 480 on the same side opposite to the substrate 310. In this case, the conductive layer on the box 476 can be patterned to independently bias the two contacts of the device. In one case, the device can be directly transferred from the cassette substrate 476 to the acceptor substrate. Here, the contacts 432 and 480 will not be directly bonded to the receptor substrate (the receptor substrate does not need to have special pads). In this case, the conductive layer is deposited and patterned to connect the contacts 432 and 380 to the appropriate connections in the receptor substrate. In another case, the device can be transferred from the cassette 476 to the temporary substrate before transferring to the recipient substrate. Here, the contacts 432 and 480 may be directly bonded to the receptor substrate pads. The device can be tested in a box or in a temporary substrate.

In another embodiment shown in FIG. 5A, the mesa structure as described above is produced on the donor substrate 510, in which different layers are etched through, such as the first bottom conductive layer 512; the functional layer 514, For example, the light-emitting layer; and the second top conductive layer 516 is formed with a micro device structure. The top contact pad 532 may be deposited before or after etching on the top of the top conductive layer 516. Moreover, each micro-device may include other passivation layers and/or MIS layers 572 surrounding each micro-device for isolation and/or protection. In this embodiment, the device may be provided with different anchors, whereby after the device is peeled off, the anchors hold the device to the donor substrate 510. This peeling can be performed by laser. In the example, the laser only scans the device. In an embodiment, a mask may be used, which only has an opening for the device on the back of the donor substrate 510 to block lasers from other regions. The mask may be separate from the donor substrate 510 or may be a part of the donor substrate. In another case, another substrate can be connected to the device to hold the device before the peeling process. In another case, a filler layer 574, such as a dielectric, may be used between the devices.

In the first shown case, the layer 592 provides for holding the device to the donor substrate 510. The layer 592 may be a separate layer or a part of the layer of the micro device that has not been etched during the formation of the mesa structure. In another case, the layer 592 may be a continuation of one of the layers 572. In this case, the layer 592 may be a metal layer or a dielectric layer (SiN or SiO ₂ or other materials). In another case, the anchor is created as a separate structure including extension 594, void/gap 596, and/or bridge 598. Here, a sacrificial layer with the same shape as the void/gap 596 is deposited and patterned. Next, the anchor layer is deposited and patterned to form the bridge 598 and/or the extension 594. The sacrificial material can be removed later to create voids/gap 596. The extension 594 can also be avoided. Similar to the previous anchor 592, the other anchor can be composed of a different structural layer. In another case, the filling layer 574 acts as an anchor. In this case, the filling layer 574 may be etched or patterned, or left as it is.

Figure 5B shows the sample after removing the filler layer 574 and/or etching the filler layer to form an anchor. In another case, after peeling, the adhesive force of the bridge layer 598 is sufficient to hold the device in place and act as an anchor. For illustration purposes only, the final device on the right side of Figure 5B is shown in one substrate 510. One or a combination of the devices can be used in the substrate.

As shown in FIG. 5C, the anchor may cover at least a portion of the periphery of the device or the entire periphery of the device, or it may be patterned to form arms 594 and 592. Any of the structures can be used for any anchoring structure.

FIG. 5D shows an example of transferring the device to the receptor substrate 590. Here, the micro device is bonded to the pad 582 or placed in a predetermined area without any pad. Pressure or separation force can release the anchor by breaking the anchor. In another case, temperature can also be used to release the anchor. The temperature can be controlled to increase the viscosity of the layer between the peeling of the micro device and the donor substrate 510 to act as an anchor. Figure 5E shows the device after it has been transferred to the receiver substrate 590 and shows possible release points 598-2 in the anchor. The anchor can also be connected to the donor substrate 510 directly or indirectly through other layers.

The device on the donor substrate 510 can be produced with two contacts 532 and 480 on the same side opposite to the donor substrate 510. In one case, the device can be directly transferred from the donor substrate 510 to the acceptor substrate 590. Here, the contacts 532 and 480 may be directly bonded to the acceptor substrate pad 582. The device can be tested in the donor substrate 510 or in a box. In another embodiment, the device may be first transferred from the donor substrate 510 to the cassette substrate before transferring to the acceptor substrate 590. Here, the contact 532 will not be directly bonded to the acceptor substrate 590, that is, the acceptor substrate 590 does not need to have a special pad 582. In this case, a conductive layer is deposited and patterned to connect the contact 532 to the appropriate connection in the acceptor substrate 590.

The system substrates or receptor substrates 390, 490, and 590 may include micro LEDs, organic LEDs, sensors, solid state devices, integrated circuits, MEMS (Micro Electro Mechanical System), and/or other electronic components. Other embodiments relate to pixel array patterning and placement of micro devices to optimize the use of micro devices in the selective transfer process. System substrates or receptor substrates 390, 490, and 590 can be, but are not limited to, printed circuit boards (PCBs), thin film transistor backplanes, integrated circuit substrates, or, in the case of optical microdevices such as LEDs, components of displays, for example Drive circuit system backplane. The patterned micro device donor substrate and acceptor substrate can be used in combination with different transfer technologies, including but not limited to using different mechanisms (for example, electrostatic transfer heads, elastomer transfer heads) or direct transfer mechanisms such as dual-function pads Pick and place (pick and place).

Fig. 6A shows an alternative embodiment of the mesa structure of Figs. 3A to 3F, where the mesa structure is initially unetched through all layers. Here, a certain part of the buffer layer 312 and/or the contact layer 312 may remain during the initial step. The mesa structure is generated on the donor substrate 310. The micro device structure is formed by etching through different layers, such as the first bottom conductive layer 312, the functional layer 314, and the second top conductive layer 316. The top contact 332 may be deposited on top of the top conductive layer 316 before or after etching. The mesa structure may include other layers 372 that will be deposited and patterned before or after the formation of the mesa structure. These layers can be dielectrics, MIS, contacts, sacrifices, etc. After the mesa structure is created, one or more filler layers 374, such as dielectric materials, are used between and around the micro devices to hold the micro devices together. The micro device is bonded to the temporary substrate 376 by one or more substrate bonding layers 378. One or more bonding layers 378 can provide one or more different forces, such as electrostatic force, chemical force, physical force, thermal force, and so on. After removing the device from the donor substrate 310, as described above, additional portions of the bottom conductive layer 312 can be etched away or patterned to separate the devices (FIG. 6C). Other layers such as contact bonding layer 380 can be deposited and patterned. Here, the filler layer 374 can be etched to separate the micro devices, or the sacrificial layer can be removed to separate the devices. In another embodiment, temperature may be applied to separate the device from the filler layer 374 and prepare it for transfer to the receptor substrate 390. This separation can be performed selectively, as described above. In another embodiment, the filler layer 374 may be etched to form a housing, base, or anchor 375 that at least partially surrounds each microdevice, for example, in the shape of a truncated cone or truncated pyramid, as shown in Figure 6E. Another layer can be deposited over the base 375 and this layer can be used to form the anchor 598-2. After the additional layer 598-2 is formed, the filler base layer 375 can be left or removed from the anchoring device. Figure 6G shows a device with a sacrificial layer 372-2. The sacrificial layer 372-2 can be removed by etching or can be thermally deformed or thermally removed.

In another embodiment, the anchor is the same as the housing 375 and is constructed of a polymer layer, an organic layer, or other layer after the microdevice is transferred to the cartridge 376. The housing 375 may have different shapes. In one case, the housing can match the shape of the device. The side wall of the housing can be shorter than the height of the micro device. The side walls of the housing can be connected to the microdevices before the transfer cycle to support the post-processing of the different microdevices in the box 376 and the packaging of the microdevice box for transportation and storage. The side wall of the housing can be separated, or the connection from the device to the micro device can be weakened by different means such as heating, etching or exposure before or during the transfer cycle.

The device on the donor substrate 310 can be produced with two contacts 332 and 380 on the same side opposite to the donor substrate 310. In this case, the conductive layer on the box 376 can be patterned to independently bias the two contacts 332 and 380 of the device. In one case, the device can be directly transferred from the cassette substrate 376 to the acceptor substrate 390. Here, the contacts 332 and 380 will not be directly bonded to the receptor substrate 390, that is, the receptor substrate 390 does not need to have special pads. In this case, a conductive layer is deposited and patterned to connect the contacts 332 and 380 to appropriate connections in the receptor substrate 390. In another embodiment, the device may first be transferred from the cassette 376 to the temporary substrate before transferring to the acceptor substrate 390. Therefore, the contacts 332 and 380 can be directly bonded to the receptor substrate pads. The device can be tested in the cassette 376 or in a temporary substrate.

Due to the mismatch between the substrate crystal lattice and the micro device layer, the growth of the layer contains several defects such as dislocations and voids. In order to reduce defects, at least one first buffer layer 6114 and/or second buffer layer 6118 with a separation layer 6116 in between or near it can be deposited on the donor substrate 6110 first, and then on the buffer layer 6114 and/or An active layer 6112 is deposited on top of 6118. The thickness of the buffer layers 6114 and 6118 can be quite large, for example, as thick as the donor substrate 6110. During the separation (peeling) of the micro device from the donor substrate 6110, the buffer layer 6114/6118 can also be separated. Therefore, the buffer layer deposition should be repeated every time. 6H shows the structure on the substrate 6110, in which the separation layer 6116 is between the first buffer layer 6114 and the actual device layer 6112. There may be a second buffer layer 6118 between the separation layer 6116 and the device layer 6112. The second buffer layer 6118 can also prevent contaminants from the separation layer 6116 from penetrating into the device layer 6112. Both buffer layers 6114 and 6118 may include more than one layer. The separation layer 6116 may also include a stack of different materials. In one example, the separation layer 6116 responds to light wavelengths to which the other layers do not respond. This light source can be used to separate the actual device 6112 from one or more buffer layers 6114/6118 and the donor substrate 6110. In another example, the separation layer 6116 reacts to chemical substances, and the same chemical substance does not affect other layers. This chemical substance can be used to remove the separation layer 6116 or change its properties to separate the device from one or more buffer layers 6114/6118 and the substrate 6110. This method keeps the first buffer layer 6114 intact on the donor substrate 6110, and therefore, the first buffer layer can be reused for the next device generation. Before the next device deposition, some surface treatments such as cleaning or buffering can be performed. In another example, one or more buffer layers 6114/6118 may include zinc oxide.

Before the separation process (stripping), the microdevices can be separated by different etching processes, as shown in FIG. 6I. The etching can etch the second buffer layer 6118 (if present), and can also etch part or all of the separation layer 6116 and the device layer 6112. In another example, the second buffer layer 6118 or the separation layer 6116 is not etched. After the etching step, the micro device is temporarily (or permanently) bonded to another substrate 6150, and the separation layer 6116 is removed or modified to separate the micro device from the first buffer layer 6114 and the second buffer layer 6118. As shown in FIG. 6J, the first buffer layer 6114 can remain substantially intact on the donor substrate 6110.

In another embodiment shown in FIGS. 6K to 6M, layers, such as the first bottom conductive layer 312, the functional layer 314, and the second top conductive layer 316, may be formed in the form of islands 6212 on the donor substrate 6210. Figure 6K shows a top view of islands 6212 formed in a micro device array. The size of the island 6212 can be the same as the box size or a multiple of the box size. The islands 6212 can be formed from the buffer layer 6114/6118 or after the buffer layer. Here, surface treatment or gaps 6262, 6263 can be formed on the surface to initiate film growth into islands (FIG. 6L). In order to process the micro device, the gap can be filled with a filler layer 6220, as shown in FIG. 6M. The filler 6220 may be composed of a polymer layer, a metal layer, or a dielectric layer. After processing the microdevice, the filler layer 6220 may be removed.

Figure 7 emphasizes the process of producing a micro device cartridge. During the first step 702, a microdevice is prepared on a donor substrate, such as 310 or 510. During this step, the device is formed, and post-processing is performed on the device. During the second step 704, the device is prepared to be separated from the donor substrate 310 or 510. This step can involve fixing the microdevice by using anchors, such as 375, 476-1, 592, 594, 598, or 598-2, and fillers, such as 374, 472, and 574. During the third step 706, a cassette or temporary substrate, such as 376 or 476, is formed from the pre-processed microdevices from the first step 702 and the second step 704. In one case, during this step, the microdevice is directly or indirectly bonded to the cassette substrate 376 or 476 via a bonding layer, such as 378 or 478. Next, the micro device is separated from the micro device cassette substrate 376 or 476. In another embodiment, the cassette is formed on a microdevice donor substrate, such as 510. After fixing the device on the cassette substrate 376, 476 or 510, other processing steps can be performed, such as removing some layers, such as 312, 374, 472, 574; or adding electrical layers (for example, contacts 380 or 480) Or optical layer (lens, reflector, etc.). During the fourth step 708, the cassette 376 or 476 is moved to the receptor substrate, such as 390, 490, or 590 to transfer the device to the receptor substrate 390, 490, or 590. Some of these steps can be rearranged or combined. When the micro device is still on a cassette substrate, such as 376 or 476, or after the micro device has been transferred to a receiver substrate, such as 390, 490, or 590, test step 707A can be performed on the micro device to determine whether the micro device is defective . The defective microdevice can be removed or repaired in situ in step 707B. For example, a predetermined number of microdevices can be tested, and if the number of defects exceeds a predetermined threshold, the entire group of microdevices can be removed, at least some of the defective microdevices can be removed and/or defective microdevices can be repaired At least some of the microdevices.

FIG. 8 shows the steps of transferring the device from the cassette 376, 476, or 510 to the receptor substrate 390, 490, or 590. Here, during the first step 802, the cassette 376, 476, or 510 is loaded (or picked up), or in another embodiment, the spare equipment arm is preloaded with the cassette 376, 476, or 510. During the second step 804, the cassette 376, 476, or 510 is aligned with part (or all) of the receptor substrate. This alignment can be performed using dedicated alignment marks on the cassette 376, 476, or 510 and the receptor substrate 390, 490, or 590 or using a micro device and the landing area on the receptor substrate 390, 490, or 590. During the third step, the microdevice is transferred to the selected landing area. During the fourth step 808, if the acceptor substrate 390, 490, or 590 is completely filled, the cassette substrate 376, 476, or 510 is moved to the next step in step 810, such as another acceptor substrate 390, 490 Or 590. If the current acceptor substrate 390, 490, or 590 needs further filling, one or more additional cassettes 376, 476, or 510 are used for additional transfer steps. Before the new transfer cycle, if the cassette 376, 476, or 510 does not have enough devices, the cycle starts from the first step 802. If the cassette 376, 476, or 510 has sufficient devices in step 812, the cassette 376, 476, or 510 is shifted (or moved and aligned) to a new area of the receptor substrate 390, 490, or 590 in step 814, and The new cycle continues to step 806. Some of these steps can be combined and/or rearranged.

9 shows the steps of transferring the device from the cassette, for example, a temporary substrate 376, 476, or 510, to a receiver substrate, such as 390, 490, or 590. Here, during the first step 902, the cassette 376 or 476 is loaded (or picked up), or in another embodiment, the spare equipment arm is preloaded with the cassette. During the second step 902-2, a group of microdevices is selected in the box 376, 476, or 510 so that the number of defects therein is less than the threshold. During the third step 904, the cassette 376, 476, or 510 is aligned with part (or all) of the receptor substrate. This alignment can be performed using dedicated alignment marks on cassettes 376, 476, or 510 and/or receptor substrates 390, 490, or 590 or using microdevices and landing areas on receptor substrates 390, 490, or 590. Then, during a third step 906, the microdevice can be transferred to the selected landing area. In the optional step 906-1, the selected microdevices in the cassette can be connected to the receptor substrate. In the optional step 906-2, the microdevice can be turned on by biasing by the receptor substrate 390, 490 or 590 to test the connection between the microdevice and the receptor substrate, for example. If an individual micro-device is found to be defective or non-functional, an additional adjustment step 906-3 can be performed to correct or repair some or all of the non-functional micro-devices.

If the acceptor substrate is completely filled, the acceptor substrate 390, 490, or 590 moves to the next step. If the acceptor substrate 390, 490, or 590 needs to be further filled, then an additional transfer step from one or more additional cassettes 376, 476, or 510 is performed. Before the new transfer cycle, if 376, 476, or 510 do not have enough devices, the cycle starts from the first step 902. If the cassette 376, 476, or 510 has sufficient devices, in step 902-2, the cassette 376, 476, or 510 is shifted (or moved and aligned) to a new area of the receptor substrate 390, 490, or 590.

FIG. 10 shows exemplary processing steps for generating a multi-type micro device box 376, 476, 510, or 1108. During the first step 1002, at least two different microdevices are prepared on different donor substrates, such as 310 or 510. During this step, the device is formed, and post-processing is performed on the device. During the second step 1004, the device is prepared to be separated from the donor substrate, such as 310 or 510. This step can involve fixing the microdevice by using anchors, such as 375, 476-1, 592, 594, 598, and 598-2, and fillers, such as 374, 472, and 574. During the third step 1006, the first device is moved to the box 376, 476, 510, or 1108. During the fourth step 1008, at least the second microdevice is moved to the box 376, 476, 510, or 1108. In one case, during this step, the micro device is directly or indirectly bonded to the cassette substrate 376, 476, 510, or 1108 via a bonding layer, such as 378 or 478. Next, the micro device is separated from the micro device cassette substrate 310 or 510. For direct transfer, different types of microdevices can have different heights. For example, the second type of microdevice transferred to the cassette 376, 476, 510, or 1108 may be slightly higher than the first type of microdevice (or for the second microdevice type, on the cassette 376, 476, 510, or 1108) The position can be slightly higher). Here, after the box 376, 476, 510, or 1108 is completely filled, the height of the micro device can be adjusted to make the surface of the box 376, 476, 510, or 1108 flat. This can be done by adding material to shorter microdevices or removing material from taller devices. In another case, the landing area on the receptor substrate 390, 490, or 590 may have different heights associated with the difference of the boxes 376, 476, 510, or 1108. Another method of filling boxes 376, 476, 510 or 1108 is based on picking. The microdevice can be moved to the cassette 376, 476, 510, or 1108 using a picking process. Here, for the microdevices in the cluster of one of the cassettes 376, 476, 510, or 1108, the force elements on the pickup head may be unified, or a single force element may be used for each microdevice. Also, the microdevice can be moved to the box 376, 476, 510, or 1108 in other ways. In another embodiment, the additional device is moved away from the cassette substrate 376, 476, 510, or 1108 of the first or second (or third or other) microdevice, and other types of microdevices are transferred to the cassette 376, 476, 510, or 1108 in the blank area. After the device is fixed on the cassette substrate 376, 476, 510, or 1108, other processing steps can be performed, such as adding filler layers 374, 474, or 574; removing some layers; or adding electrical layers (for example, contacts 380, 480 or 580) or optical layer (lens, reflector). The device can be tested after or before the device is used to fill the receptor substrate 390, 490, or 590. The test can be an electrical test or an optical test or a combination of both. This test can identify defects and/or performance of the device on the box. During the last step 1010, the cassette 376, 476, 510, or 1108 is moved to the receptor substrate 390, 490, or 590 to transfer the device to the receptor substrate 390, 490, or 590. Some of these steps can be rearranged or combined.

The transfer process described here (e.g., Figures 7, 8, 9 and 10) may include a stretching step for increasing the spacing of the microdevices on the cassette 376, 476, 510, or 1108. This step can be performed before the alignment or can be part of the alignment step. This step can increase the number of micro devices aligned with the landing area (or pad) on the receptor substrate 390, 490, or 590. In addition, this step can match the spacing between the micro device arrays including at least two micro devices on the cassette 376, 476, 510 or 1108 to match the landing area (or pad 382) on the receptor substrate 390, 490 or 590 Pitch.

FIG. 11 shows an example of a multi-type micro device cartridge 1108 similar to the temporary substrate 376, 476, or 510. The cartridge 1108 contains three different types of micro-devices 1102, 1104, and 1106 in colors (red, green, and blue). But there can be more device types. The distances x1, x2, and x3 between the micro devices are related to the pitch of the landing area in the receptor substrate 390, 490, or 590. After several devices that may be related to the pixel pitch in the receptor substrate 390, 490 or 590, there may be different pitches x4, y2. This pitch compensates for the mismatch between the pixel pitch and the micro device pitch (landing area pitch). In this case, if pick-and-place is used to produce the cassette 1108, the force element may take the form of a column corresponding to each micro device type, or the force element may be a separate element for each micro device.

FIG. 12 shows an example of a multi-type micro device cartridge 1208 similar to the temporary substrate 376, 476, or 510. The cartridge 1208 contains three different types of micro-devices 1202, 1204, and 1206 in colors (red, green, and blue). The other area 1206-2 may be empty, filled with spare micro devices, or contain a fourth different type of micro devices. The distances x1, x2, and x3 between the micro devices are related to the pitch of the landing area in the receptor substrate 390, 490, or 590. After several device arrays that may be related to the pixel pitch in the receptor substrate 390, 490, or 590, there may be different pitches x4, y2. This pitch compensates for the mismatch between the pixel pitch and the micro device pitch (landing area pitch).

FIG. 13 shows an example of a microdevice 1302 prepared on a donor substrate 1304 similar to the donor substrate 310 or 510 before being transferred to the multi-type microdevice cassette 376, 476, 510, 1108, 1208. Here, the support layers 1306 and 1308 can be used for a single device or a group of devices. Here, the spacing may match the spacing in the boxes 376, 476, 510, 1108, 1208, or the spacing may be a multiple of the box spacing.

In all the above structures, before filling the substrate with the microdevice, the microdevice can be moved from the first box to the second box. Additional processing steps can be performed after the transfer, or some of the processing steps can be divided between the first cassette structure and the second cassette structure.

FIG. 14A shows an embodiment of a microdevice in a donor substrate 1480 similar to the donor substrate 310 or 510. Due to manufacturing defects and material defects, the output power of the micro device on the donor substrate 1480 may gradually decrease or increase, that is, there is unevenness, as shown by the coloring from dark to light. Since devices can be transferred together into a block, such as block 1482 or devices can be transferred into the receptor substrate 390, 490, or 590 one or more at a time in sequence, adjacent ones of the receptor substrates 390, 490, or 590 The device is gradually degrading. However, where one block, such as 1482 or a series of adjacent blocks ends and another block, such as 1483 or another series of blocks begins, for example along the intersection line 1484, a worse problem may occur, which may cause output The sudden change in performance is shown in Figure 14B. This sudden change may cause visual artifacts in optoelectronic devices such as displays.

In order to solve the problem of unevenness, one embodiment shown in FIG. 14C includes using separate blocks 1482 and 1483 above and below the display to skew or stagger the separate blocks so that the edges of the blocks or cross The lines are not clear lines, thereby eliminating the crossing lines 1484, and thereby, the device blocks form a skewed pattern on the display. Therefore, the average impact of the sharp transition is significantly reduced. The deflection can be random and can have different profiles.

FIG. 14D shows another embodiment in which the microdevices in adjacent blocks are turned over so that devices with similar performance are adjacent to each other, for example, the performance in the first block 1482 decreases from the first outside A to the first inside B , And the performance of the second adjacent block 1483 increases from the second inner side B adjacent to the first inner side B to the second outer side A, which can keep the changes and transitions between the blocks very smooth and eliminate the long sharp crossing 1484.

Figure 14E shows an exemplary combination of flipping devices, for example, alternating high-performance devices and low-performance devices on the inside and skewing the edges to further improve average uniformity. In the illustrated embodiment, the device performance alternates between high and low in two directions, namely in adjacent horizontal blocks and adjacent vertical blocks.

In one case, before transferring to the receiver substrate 390, 490 or 590, the performance of the microdevice at the edge of the block is matched for the adjacent transferred block (array).

FIG. 15A shows the use of two or more blocks 1580, 1582 to fill blocks in the receptor substrate 1590. In the illustrated embodiment, the skew or flip method can be used to further improve the average uniformity, as shown in Figure 15B. The higher (or lower) output power sides B and C from blocks 1580 and 1582, respectively, can be positioned adjacent to each other. In addition, the connections of the blocks above and below the blocks are also used to bias the connections between the blocks. Oblique or staggered. Also, random or defined patterns can be used to fill a box or receptor substrate 1590 with more than one block.

Figure 16A shows a sample with more than one block 1680, 1682, and 1684. The blocks 1680, 1682, and 1684 may be from the same donor substrate 310 or 510 or from different donor substrates 310 or 510. Figure 16B shows an example of filling the box 1690 with different blocks 1680, 1682, and 1684 to eliminate any unevenness found in the blocks.

17A and 17B show a structure with a plurality of boxes 1790. As described above, the position of the cassette 1790 is selected in such a way that the same area in the receptor substrate 390, 490, 590, or 1590 overlaps the cassette 1790 with the same micro device during different transfer cycles. In one example, the cassettes 1790 may be independent, which means that a separate arm or controller handles each cassette independently. In another embodiment, the alignment can be performed independently, but other operations can be performed simultaneously. In this embodiment, the receptor substrate 390, 490, 590, or 1590 can be moved so as to be easily transferred after alignment. In another example, the boxes 1790 are moved together for easy transfer after alignment. In another example, the cassette 1790 and the receptor substrate 390, 490, 590, or 1590 can be moved for easy transfer. In another case, the cartridge 1790 can be assembled in advance. In this case, the frame or the base plate can hold the assembled box 1790.

The distance X3 and Y3 between the boxes 1790 may be a multiple of the width X1, X2 or the length Y1, Y2 of the box 1790. The distance can be a function of the movement steps in different directions. For example, X3 = KX1 + HX2, where K is the moving step to the left (directly or indirectly) in order to fill the acceptor substrate 390, 490, 590 or 1590, and H is to fill the acceptor substrate to the right ( Directly or indirectly) the move step. The same principle can be used for the distance Y3 between the boxes 1790 and the lengths Y1 and Y2. As shown in Figure 17A, the cassette 1790 can be aligned in one or two directions. As shown in Figure 17B, in another example, the cassette 1790 is not aligned in at least one direction. Each cassette 1790 may have independent controls for applying pressure and temperature to the receptor substrate 390, 490, 590, or 1590. Depending on the direction of movement between the receptor substrate 390, 490, 590 or 1590 and the cartridge 1790, other arrangements are also possible.

In another example, the cassette 1790 may have different devices and therefore fill different areas in the receptor substrate 390, 490, 590, or 1590 with different devices. In this case, the relative positions of the cassette 1790 and the receptor substrate 390, 490, 590, or 1590 are changed after each transfer cycle to fill different areas with all required microdevices from different cassettes 1790.

In another embodiment, several cassette arrays 1790 are prepared. Here, after the device is transferred from the first cassette array to the receptor substrate 390, 490, 590, or 1590, the receptor substrate 390, 490, 590, or 1590 moves to the next micro device array to fill the receptor substrate 390, 490 , 590 or 1590 in the remaining area or receive different devices.

In another example, the cassette 1790 may be on a curved surface, and thus circular movement will provide contact points to transfer the microdevice into the receptor substrate 390, 490, 590, or 1590.

The vertical optoelectronic stack layer includes a substrate, an active layer, at least one buffer layer between the active layer and the substrate, and at least one separation layer between the buffer layer and the active layer, wherein the buffer layer can be kept at While on the substrate, the active layer is physically removed from the substrate by changing the properties of the separation layer.

In one embodiment, the process of changing the properties of the one or more separation layers includes chemically reactive etching or deforming the separation layer.

In another embodiment, the process of changing the properties of the one or more separation layers includes exposure to photoelectron waves, thereby deforming the separation layer.

In another embodiment, the process of changing the properties of the one or more separation layers includes changing the temperature, thereby deforming the separation layer.

In one embodiment, reusing the buffer layer to create a new optoelectronic stack layer includes surface treatment.

In one embodiment, the surface treatment uses chemical or physical etching or polishing.

In another embodiment, the surface treatment uses the deposition of an additional thin layer or buffer layer to reform the surface.

In one embodiment, the optoelectronic device is an LED.

In one embodiment, the separation layer is zinc oxide.

Embodiments of the present invention include a continuous pixelated structure including a fully or partially continuous active layer, a pixelated contact layer and/or a current spreading layer.

In this embodiment, there may be a pad layer and/or a bonding layer on top of the pixelated contact layer and/or the current spreading layer.

In the above embodiments, there may be a dielectric opening on top of each pixelated contact layer and/or current spreading layer.

Another embodiment includes a donor substrate including microdevices with bonding pads and a filler layer filling the spaces between the microdevices.

Another embodiment includes a temporary substrate that includes a bonding layer to which microdevices from the donor substrate are bonded.

Another embodiment includes heat transfer technology, which includes the following steps:

1) Align the micro device on the temporary substrate with the bonding pad of the system substrate;

2) Verify that the melting point of the bonding pad on the system substrate is higher than the melting point of the bonding layer in the temporary substrate;

3) Generate a thermal profile that melts both the bonding pad and the bonding layer, and thereafter keeps the bonding layer melted and the bonding pad remains solidified; and

4) Separate the temporary board from the system board.

In another embodiment of the transfer technique, the thermal profile is generated by local or global heat sources or both.

Another embodiment includes a micro device structure, in which after the micro device is released from the donor substrate by a peeling process, at least one anchor holds the device to the donor substrate.

Another embodiment includes a transfer technique for the structure of a micro device, in which the anchor releases the micro device after or during the bonding of the micro device to the pad in the receptor substrate by pushing or pulling force.

In another embodiment, the anchor according to the micro device structure is composed of at least one layer extending from the side of the micro device to the substrate.

In another embodiment, the anchor according to the microdevice structure is composed of a void or at least one layer on top of the void.

In another embodiment, the anchor according to the microdevice structure is composed of a filling layer surrounding the device.

Another embodiment includes a structure according to the micro device structure, in which the viscosity of the layer between the peeled micro device and the donor substrate is increased by controlling the temperature to act as an anchor.

Another embodiment includes a release process for anchors in a microdevice structure, where the temperature is adjusted to reduce the force between the anchor and the microdevice.

Another embodiment includes a process of transferring the microdevice to the receptor substrate, wherein the microdevice is formed in a box; aligning the box with a selected landing area in the receptor substrate; and associating the box with the selected landing area The microdevices are transferred to the receptor substrate.

Another embodiment includes the process of transferring the microdevices to the receptor substrate, wherein the microdevices are formed in a box; selecting a group of microdevices with defective microdevices smaller than a threshold; combining the selected group of microdevices in the cassette with The selected landing area in the receptor substrate is aligned; and the microdevices associated with the selected landing area in the cassette are transferred to the receptor substrate.

An embodiment includes a cartridge with multiple types of microdevices transferred into it.

An embodiment includes a micro device box, wherein a sacrificial layer separates at least one side of the micro device from a filler layer or a bonding layer.

In an embodiment, the sacrificial layer is removed to release the microdevice from the filler layer or bonding layer.

In an embodiment, the sacrificial layer releases the microdevice from the filler under some conditions such as high temperature.

The micro device can be tested to extract information related to the micro device, including but not limited to defects, uniformity, operating conditions, etc. In one embodiment, one or more microdevices are temporarily bonded to the cartridge, which has one or more electrodes for testing the microdevice. In one embodiment, another electrode is deposited after the microdevice is positioned in the cassette. This electrode can be used to test microdevices before or after patterning. In one embodiment, the box is placed in a predetermined position (the predetermined position may be a holder). The cassette and/or the receptor substrate are moved for alignment. At least one selected device is transferred to the receptor substrate. If more micro-devices are available on/in the cassette, the cassette or receptor substrate is moved to align with a new area or new receptor substrate in the same receptor substrate, and at least another selected device is transferred to a new location. This process can continue until the cartridge does not have enough microdevices, at which point the new cartridge can be placed in a predetermined position. In one example, the transfer of the selected device is controlled based on information extracted from the box. In one example, the defect information extracted from the cassette can be used to limit the number of defective devices transferred to the acceptor substrate to less than the threshold number by eliminating the transfer of a set of devices whose number of defects exceeds the threshold. The cumulative number of transfer defects will exceed the threshold. In another example, the boxes will be binned based on one or more extracted parameters, and each bin will be used for a different application. In another case, a cassette with similar performance based on one or more parameters will be used in a receptor substrate. The examples presented here can be combined to improve box transfer performance.

In embodiments, physical contact and pressure and/or temperature may be used to transfer the device from the cassette to the receptor substrate. Here, the pressure and/or temperature can generate a bonding force (clamping force) for holding the micro device to the receptor substrate, and/or temperature can reduce the contact force between the micro device and the cartridge. Therefore, the transfer of the micro device to the acceptor substrate is achieved. In this case, the position assigned to the microdevice on the receptor substrate may have a higher profile than the rest of the receptor to enhance the transfer process. In an embodiment, the cassette does not have a microdevice in an area that may be in contact with a useless area of the receptor substrate, such as a location allocated to other types of microdevices during the transfer process. These two instances can be combined. In an embodiment, the allocated position of the microdevice on the substrate may have been wetted with the adhesive or the position may have been covered with a bonding alloy, or an additional structure may be placed on the allocated position. In the stamping process, a separate box, printing or other processes can be used. In an embodiment, the selected microdevices on the cassette can be moved closer to the receptor substrate to enhance selective transfer. In another case, the recipient substrate exerts a pulling force to assist or initiate the transfer of the microdevice from the cassette. The pulling force can be combined with other forces.

In one embodiment, the housing can support the microdevice in the cartridge. The housing can be made around the micro device on the donor substrate or the box substrate or made separately, and then the micro device is moved inside and bonded to the box. In one embodiment, at least one polymer (or another type of material) may be deposited on top of the cassette substrate. The microdevices from the donor substrate are pushed into the polymer layer. The microdevice is selectively or generally separated from the donor substrate. The layer can be cured before or after the device is separated from the donor substrate. This layer can be patterned, especially if multiple different devices are integrated into the box. In this case, the layer can be created for one type, and the micro device is buried in the layer and separated from its donor. Then, another layer is deposited and patterned for the next type of microdevice. Then, the second microdevice is buried in the associated layer. In all cases, this layer can cover part or all of the microdevices. In another case, the housing is constructed from a polymer layer, an organic layer, or other layers after the microdevice is transferred to the cartridge. The housing can have different shapes. In one case, the housing can match the shape of the device. The side wall of the housing can be shorter than the height of the micro device. The side wall of the housing can be connected to the micro device before the transfer cycle to provide support for the post-processing of the different micro devices in the box and the packaging of the micro device box for transportation and storage. The side wall of the housing can be separated, or the connection from the device to the micro device can be weakened by different means such as heating, etching or exposure before or during the transfer cycle. There may be contact points that hold the microdevice to the cassette substrate. The point of contact to the box can be the bottom or top side of the device. The contact points can be weakened or eliminated by different methods such as heating, chemical processes, or exposure before or during the transfer. This process can be performed for some selected devices or it can be performed globally for all micro devices on the cartridge. The contacts can also be conductive to enable testing of the microdevice by biasing the device at the contact and other electrodes connected to the microdevice. During the transfer cycle, the cassette can be under the receiver substrate to prevent the microdevice from falling off the housing if the contacts are globally removed or weakened.

In one embodiment, the microdevice cartridge may include at least one anchor that holds the microdevice to the surface of the cartridge. The cassette and/or the receptor substrate are moved so that some of the microdevices in the cassette are aligned with some positions in the receptor substrate. This anchor can be broken under pressure during pushing the box and the receptor substrate towards each other or pulling the device by the receptor substrate. The micro device can stay permanently on the receptor substrate. The anchor can be on the side of the microdevice or on the top (or bottom) of the microdevice.

The top side is the side of the device facing the box, and the bottom is the opposite side of the micro device. The other sides are called sides or side walls.

In one embodiment, the micro device can be tested to extract information related to the micro device, including but not limited to defects, uniformity, operating conditions, and the like. The box can be placed in a predetermined position (the predetermined position can be a holder). The cassette and/or the receptor substrate can be moved for alignment. At least one selected microdevice can be transferred to the acceptor substrate. If more microdevices are available on/in the cassette, the cassette or receptor substrate can be moved to align with a new area or new receptor substrate in the same receptor substrate, and at least another selected device can be transferred to the new position. This process can continue until the cassette does not have enough microdevices, at which point the new cassette will be placed in the predetermined position. In one case, the transfer of the selected device can be controlled based on information extracted from the box. In one case, the defect information extracted from the cassette can be used to eliminate the number of defective devices that will be transferred to the acceptor substrate by removing the number of defective devices whose number of defects exceeds the threshold or the cumulative number of transferred defects exceeds the threshold. Limited to the number below the threshold. In another case, the boxes will be binned based on one or more extracted parameters, and each bin can be used for different applications. In another case, a cassette with similar performance based on one or more parameters can be used in a receptor substrate. The examples presented here can be combined to improve box transfer performance.

One embodiment includes a method of transferring a device to a receiver substrate. The method includes:

a) A cassette is prepared, the cassette has a substrate, wherein the micro device is positioned on at least one surface of the cassette substrate, and the substrate has a greater amount in an area other than the location of the micro device of the same size corresponding to the area in the receptor substrate Multi-micro devices.

b) Test the device on the box by extracting at least one parameter.

c) Pick up the cassette or transfer the cassette to a location with a micro device facing the receptor substrate.

d) Use the test data to select a group of micro devices on the box.

e) Align the selected group of microdevices on the cassette with the selected location on the receptor substrate. The set of microdevices is transferred from the cassette to the receptor substrate.

f) Processes d and e can continue until the cassette does not have any useful devices or the receptor substrate is completely filled.

One embodiment includes a cassette with more than one type of microdevices positioned in the cassette at the same pitch as in the receptor substrate.

One embodiment includes a box having a substrate, wherein the micro-devices are positioned (directly or indirectly) on its surface, and the micro-devices are skewed in any column or row so that the edge of at least any column or row does not overlap with at least another column or row. Align the edges of the rows.

One embodiment is a method of transferring a device to a receptor substrate. The method includes transferring an array of micro devices into a substrate, wherein the edges of the transferred micro devices in at least any column or row are not aligned with the edges of the transferred devices in at least another column or row.

One embodiment includes a method of transferring a device to a receiver substrate. The method includes transferring an array of devices from a donor substrate to an acceptor substrate, wherein in any area on the acceptor substrate that is similar in size to the transferred array, there are at least two regions corresponding to the transferred array from the donor substrate. Any column or row of micro devices in different regions.

One embodiment includes the process of transferring the array of microdevices to the receptor substrate, where the microdevices are deflected at the edges of the array to eliminate sudden changes.

Another embodiment includes a process of transferring a micro device array to a receiver substrate, wherein the performance of the micro devices at the adjacent edges of the two micro device arrays is matched before the transfer.

Another embodiment includes a process of transferring the micro device array to the acceptor substrate, wherein the micro device array is filled from at least two different areas of the micro device donor substrate.

Another embodiment includes a process of transferring the micro device array from the cassette to the receptor substrate, wherein several micro device cassettes are placed in different positions corresponding to different areas of the receptor substrate, and then the cassettes are aligned with the receptor substrate , And transfer the micro device from the box to the acceptor substrate. Different anchor solutions for fixing the microdevice on the donor substrate

The process of integrating microdevices into the system substrate involves generating and preparing a donor substrate, transferring a preselected array of microdevices to the acceptor substrate, and then (or simultaneously) electrically or mechanically bonding the microdevice and the system substrate. During the bonding between the two substrates, a curing agent is applied before or after the alignment of the micro device and the system substrate to assist in forming a strong bond. The curing agent includes one of the following: polyamide, SU8, PMMA, BCB film layer, epoxy resin, and UV curable adhesive, and curing is performed in one of the following: electric current, light, heat or mechanical force Or chemical reaction. However, the current/voltage requirements for curing may be higher than the current/voltage requirements that the microdevice can withstand.

In order to avoid damage to the micro device, a structure and method for integrating the micro device into a system substrate with enhanced bonding and conductivity capabilities are required. And can form another/alternative current/voltage path to avoid damage to the micro device.

According to an embodiment, a bonding structure may be provided. The bonding structure may include a plurality of microdevices on the donor substrate, each microdevice including one or more conductive pads formed on the surface of the microdevice; and the temporary material covers each microdevice or the one or more conductive pads. At least part of the pad.

In one case, the temporary material acts as an anchor, which holds the plurality of microdevices inside the housing structure in the donor substrate.

In another case, all or part of the micro device can be covered with a temporary conductive material, which can redirect current through the temporary conductive material instead of the micro device, and thus avoid damage to the micro device.

In one case, the micro device may have one conductive pad on each side of the micro device. In another case, the microdevice may have more than one conductive pad on one side.

FIG. 18 shows a donor substrate 1802 holding a plurality of micro devices via a donor force element according to an embodiment of the present invention. The donor substrate 1802 may be a growth substrate (in which a micro device is manufactured or grown) or another temporary substrate that has been transferred to it. The following is described with reference to gallium nitride (GaN)-based LEDs, however the structure currently described can be used for any type of LED with different material systems.

Generally speaking, GaN-based micro LEDs are manufactured by depositing a stack of materials on a sapphire substrate. A conventional GaN LED device includes a substrate such as sapphire, an n-type GaN layer formed on the substrate, or a buffer layer (such as GaN), an active layer/semiconductor layer, such as a multiple quantum well (MQW) layer and a p-type GaN layer.

As shown in FIG. 18, the plurality of microdevices on the donor substrate 1802 may have conductive pads 1814, 1816 on both the top and bottom of the stack 1806 of semiconductor layers. The receptor substrate 1808 has at least one force-receiving element 1818 for each selected microdevice selected for transfer to the receptor substrate 1808. In one case, the force receiving element is a current/voltage curable component. Here, a current/voltage 1810 is applied to the selected force-receiving element (e.g., 1818), thereby causing it to harden and holding the microdevice in place. In one example, the force-receiving element may include monomers that form a polymer under an applicable charge. In another example, the force-receiving element is a medium with high resistance traces that generate heat at an applicable current/voltage, and the generated heat locally solidifies the medium.

The donor substrate 1802 has at least one donor force element 1804. The donor force component 1804 is a component that loses its adhesive properties under current or voltage. Here, voltage/current 1812 is applied to the donor force element 1804 holding the selected device for transfer. In one example, the donor force element is a polymer that decomposes (oxidizes) under the application of electric charge. In another example, the donor force element is a highly resistive trace that burns at an applicable current/voltage.

Figure 19 shows a microdevice with more than one conductive pad on one side according to an embodiment of the present invention. Here, in one example, the microdevice may have two conductive/contact pads 1904, 1906 at the bottom of the semiconductor layer stack on the donor substrate 1902. The receptor substrate 1908 has a force-receiving element 1918, which corresponds to the contact pad for each micro device selected for transfer to the receptor substrate 1908. The force-receiving element is a current/voltage curable component. Here, a current/voltage 1910 is applied to the selected force-receiving element (e.g., 1918), thereby causing it to harden and holding the microdevice in place.

Voltage/current 1910, 1912 can be applied to selected force-receiving elements (e.g., 1918) to cure them, thereby causing them to harden and holding the microdevices in place.

In one case, the microdevice can be used as part of the bias loop. Here, voltage/current 1914 may be applied via the donor substrate 1902, or voltage/current 1910, 1912 may be applied to the acceptor substrate 1908, which passes through the microdevice and passes through either the donor substrate 1902 or the acceptor substrate 1908.

However, the current/voltage requirements of curing the force-receiving element may be higher than the current/voltage requirements of the microdevice. In order to avoid damage to the micro device, another/alternative current/voltage path can be formed. In another case, part or the entire micro device of the micro device can be covered with a temporary conductive material, which can redirect the current through the temporary conductive material instead of the micro device, and avoid damaging the micro device.

Figures 20A-20I illustrate examples of microdevices partially/completely covered with temporary conductive materials according to some embodiments of the present invention.

Part or all of the micro device can be covered by a temporary conductive material, which can redirect current through the temporary conductive material instead of the micro device, and thus avoid damage to the micro device. In one case, the temporary material may be a temporary conductive material. The conductive material can be used as a sheet or trace to connect with the same conductive material or different conductive materials on the donor substrate.

In one embodiment, the micro device may be inside the housing structure. There may be a sacrificial layer between the shell wall and the micro device. In another embodiment, there may also be a bonding material between the donor substrate, the micro device, and the conductive pad (a material similar to the housing wall) or a combination thereof.

In one embodiment, the temporary layer can also act as an anchor to hold the device in place. In another embodiment, there may be anchors that hold the microdevice into the donor substrate. The anchor can be the same or different material from the shell material. In one case, the housing can extend almost to the edge of the micro device. In another case, the housing wall is shorter than the micro device. It is also possible to have a higher housing than the micro device.

In another case, the temporary conductive material may be replaced by a non-conductive material.

For cases with both conductive and non-conductive temporary materials, the temporary material can hold the microdevice in place after removing or releasing the sacrificial layer. The micro device can be transferred to another substrate. During the transfer process, the temporary material is removed or separated from the housing structure. The separation process can be mechanical (e.g., push or pull), optical, thermal, or chemical.

The microdevice can be covered with a temporary material/layer before being transferred to the receptor substrate, or it can be covered after being transferred to the receptor substrate. In one case, the housing material is coated on the substrate between the microdevices. It can be bonded to the donor substrate, and then the shell material can be cured. In another case, there may be different materials used on the surface of the donor substrate that can be electrically coupled to the microdevice or temporary layer. In another case, the shell material is coated on top of the donor substrate. Then, the microdevices are bonded and pushed into the material, and then the material is cured. The housing material can be epoxy, polymer or other types of materials. In one case, BCB or polyamide can be used as the shell material.

The temporary material can be patterned to form an opening on the top of the donor substrate. This opening can facilitate a certain process such as removing the sacrificial layer to separate the micro device from the side wall of the housing.

20A1-20A2 show examples of highlighting the temporary conductive material covering the surface of the micro device according to some embodiments of the present invention.

Referring to FIG. 20A1, here, the micro device is inside the housing structure 2006a. There may be a sacrificial layer between the housing structure/wall 2006a and the micro device 2016. In one case, the sacrificial layer 2008a may be a patterned sacrificial layer to cover the length of the casing. In another case, the sacrificial layer 2008b can be set to the length of the micro device. Between the donor substrate and the micro device may be a bonding material 2010a, a conductive pad 2004a, or a material similar to the shell wall or a combination thereof. And the anchor 2014a can hold the micro device in the donor substrate. The anchor can be the same or different material from the shell material. The temporary conductive material 2002a can cover the surface of the micro device 2016 including the conductive pad 2004a and the housing 2006a. This structure facilitates the transfer of micro devices, thereby inspecting defective micro devices on the system substrate.

In another embodiment, the housing wall can extend almost to the edge of the micro device.

20A2 shows a cross-sectional view of a micro device on a device (donor) substrate according to an embodiment of the present invention, where the temporary conductive material does not cover the entire surface of the micro device. Here, the housing 200b and the sacrificial layer 2008b can almost extend to the edge of the micro device 2016. The temporary conductive material 2002a may include a conductive pad 2004a. Traces on the donor substrate or the conductive layer between the donor substrates can couple the conductive material to a current/voltage source.

20B1 shows a cross-sectional view of a micro device on a device (donor) substrate according to an embodiment of the present invention, in which a temporary conductive material covers a part of the conductive pad of the micro device. Here, the conductive pad such as 2004c is a patterned conductive pad, and the sacrificial layer 2008c is also a patterned sacrificial layer deposited around the micro device and the conductive pad. The temporary conductive material 2002a may cover the surface of the micro device 2016 including the conductive pad 2004a and a part of the housing 2006a. In another case, the sacrificial layer may only extend to a part of the micro device. The temporary conductive material 2002a can be coupled to a current source/voltage to promote curing or debonding. Traces on the donor substrate or the conductive layer between the donor substrates can couple the conductive material to a current/voltage source.

Figure 20B2 shows a cross-sectional view of a microdevice on a device (donor) substrate according to an embodiment of the present invention, where the temporary conductive material does not cover the entire surface of the microdevice. Here, the housing 2006b may extend almost at the edge of the micro device. The temporary conductive material 2002a may include a part of the conductive pad 2004b.

Figure 20C1 shows an example of temporary conductive material that forms a current/voltage path between conductive pads 2004c, 2006c, where the conductive pads can be on the top and bottom or the same side of the microdevice. Here, the temporary conductive material 2002c also covers the micro device, which facilitates the selective transfer of the micro device to the system substrate. This structure helps to redirect the current through the temporary conductive material instead of the micro device, and thus avoid damage to the micro device.

FIG. 20C2 shows an example in which there is no bonding material between the donor substrate and the micro device. The temporary conductive material forms a current/voltage path between the conductive pads 2004c, 2006c, where the conductive pads can be on the top and bottom or the same side of the microdevice. The temporary conductive material 2002c also covers one of the surfaces of the micro device. Here, the temporary conductive material serves as a bonding material to the microdevice.

20D shows another example of the temporary conductive material 2002d that forms a current/voltage path between the conductive pads 2004d, 2006d of the micro device when the temporary conductive material 2002d and the conductive pad do not cover the entire surface of the micro device. Here, conductive pads such as 2004d are patterned conductive pads, and temporary materials are deposited on the patterned conductive pads.

Figure 20E shows another example in which the temporary conductive material 2002e forms a current/voltage path for more than one pad on the surface of the microdevice. Here, the conductive material shorts the conductive pad on the surface of the micro device. The conductive material covers the pads 2004e, 2006e or is connected to the pads 2008e, 2010e. And (directly or indirectly) traces on the donor substrate can connect some conductive materials together. Here, the conductive material may partially or completely cover the conductive pad according to the voltage and current requirements.

FIG. 20F shows an example of conductive pads 2008f, 2010f on the surfaces that are not shorted together by the conductive layer 2002f. Here, the pad may be completely or partially covered by the conductive layer 2002f, as shown. And there is no bonding material between the donor substrate and the micro device. Temporary conductive materials serve as bonding materials for microdevices.

Figure 20G shows another example in which a temporary conductive material 2002g forms a current/voltage path for more than one pad on the surface of the microdevice. Here, the conductive material forms a path between the surface facing the donor substrate and the surface away from the donor substrate. And in one case, it shorted the pad to the surface. Here, the conductive material covers the conductive pads 2012g, 2014g or is connected to the conductive pads 2008g, 2010g.

FIG. 20H shows an example of conductive pads 2008h, 2010h on the surfaces that are not shorted together by the conductive layer 2002h. Here, the conductive pads 2012h, 2014h may be completely covered, or the conductive pads 2008h, 2010h may be partially covered, as shown. In all cases, the conductive material 2004h can directly couple the surface away from the donor substrate to the conductive layer at the donor substrate. In another case, it indirectly couples the surface away from the donor substrate to the conductive layer 2006h at the donor substrate.

20I1 and FIG. 20I2 show examples in which there are no conductive pads on the surface away from the donor substrate. Here, there are no conductive pads on the surface of the micro device away from the donor substrate. In this case, the temporary material 2002h holds the device in place after removing the sacrificial layers 2006a, 2008a. The temporary material is removed or separated from the housing after the microdevice is transferred to another substrate, so that the microdevice is released from the donor substrate.

21A-21D show top views of different micro-devices constructed with temporary materials (conductive or non-conductive) according to an embodiment of the present invention. The temporary material can be patterned to form an opening on the top of the donor substrate. This opening can facilitate a certain process such as removing the sacrificial layer to separate the micro device from the side wall of the housing. This treatment can be performed before or after the microdevice is transferred to the acceptor substrate. In one case, chemical etching can be used to remove (or modify) the sacrificial layer. In another case, electromagnetic signals (such as microwaves or light) can be used to release the device by removing/modifying the sacrificial layer. Here, the temporary layer can also act as an anchor to hold the device in place. If the temporary layer does not assist the bonding process, it does not need to connect (or cover) the pads on the micro device.

Figure 21A shows an exemplary top view representation of Figure 20A according to an embodiment of the invention. Here, the micro device 2102 on the donor substrate 2104 has a conductive pad 2106 surrounded by a temporary conductive material 2108 and a sacrificial layer 2110. Here, the traces of conductive material on the top of the donor substrate can be connected as nets, columns or rows. There may be access points on top of the donor substrate to bias the temporary layer via traces.

Figure 21B1 shows an exemplary top view representation of Figure 20B. Here, the traces on the top of the donor substrate can be connected as a net, column or row. There may be access points on top of the donor substrate to bias the temporary layer via traces. The micro device 2102 on the donor substrate 2104 has a patterned conductive pad 2106-1 surrounded by a sacrificial layer 2110. The traces of temporary conductive material on the top of the donor substrate can be connected as a net, column or row. There may be access points on top of the donor substrate to bias the temporary layer via traces.

FIG. 21B2 shows an example in which the temporary material is not connected to the pad. The micro device 2102 on the donor substrate 2104 has a conductive pad 2106-2 surrounded by a sacrificial layer 2110, and the traces of temporary conductive material on the top of the donor substrate can be connected as a mesh, column, or row. This can be used in other embodiments or related structures in the present invention.

FIG. 21C shows the exemplary top view representation of FIG. 20E in which the microdevice 2102 has more than one pad (2106-3, 2106-4) on the donor substrate 2104 surrounded by the temporary conductive material 2108 and the sacrificial layer 2110. Here, the traces on the top of the donor substrate 2104 can be connected as a net, column or row. And the traces of each pad can be processed in a separate connection group. There may be access points on top of the donor substrate to bias the temporary layer via traces.

21D shows an exemplary top view representation of FIG. 20F, in which the microdevice 2102 has more than one patterned conductive pads (2106-3, 2106-4) on a donor substrate 2104 surrounded by a temporary conductive material 2108 and a sacrificial layer 2110 on. Here, the traces on the top of the donor substrate 2104 can be connected as a net, column or row. And the traces of each pad can be processed in a separate connection group. There may be access points on top of the donor substrate to bias the temporary layer via traces. Release of microdevices from donor substrate via breakable anchor

Some embodiments of the present invention show that the micro device can be provided with different temporary anchors, whereby after peeling off the device, the temporary anchors hold the device to the donor substrate and can selectively move toward or away from the surface of the donor substrate. Therefore, when the donor substrate becomes close to the acceptor substrate, some selected devices are close to or connected to the acceptor substrate, while other micro devices are still at a significant distance from the acceptor substrate. After or during the micro device is bonded to the pad in the acceptor substrate by either pushing or pulling force, the temporary anchor releases the micro device. The anchor can break under pressure during pushing the donor substrate and the acceptor substrate toward each other or pulling the micro device by the acceptor substrate. The microdevice can be permanently held on the receptor substrate. The anchor can be on one side of the microdevice or at the top (or bottom) of the microdevice.

22A-22C show a microdevice on a donor substrate according to an embodiment of the present invention, wherein the microdevice can be selectively moved toward or away from the surface of the donor substrate.

Referring to FIG. 22A, according to one embodiment, the stack includes electrodes 2204, 2206 and an electroactive polymer (EPE) layer 2208 formed under the microdevice (eg, 2210, 2212 on top of the donor substrate 2214). The movement of the donor substrate and/or the acceptor substrate causes some microdevices in the donor substrate to become aligned with some positions in the acceptor substrate. In one case, applying a voltage to the stack causes the stack to become thinner and thus brings the device closer to the surface of the receptor substrate.

Referring to FIG. 22B, according to another embodiment, the stack includes electrodes 2208, 2206 and an electroactive polymer (EPE) layer 2222 formed under the microdevice (eg, 2210, 2212 on top of the donor substrate 2214). In one case, the electrodes can be arranged around the EPE layer. The EPE layer can be thin or thick as required. When voltage is applied to the stack including the electrodes and the EPE layer, the stack becomes thicker. In one case, the housing and anchors can also hold the micro-devices 2210 and 2212 in place.

FIG. 22C shows another example where the stacked electrodes and the micro-device 2210, 2212 structure on top of the EPE 2222, 2220 are surrounded by a housing structure 2226. In addition, the anchor 2234 holds the micro devices 2210 and 2212 inside the housing structure 2226. In another case, the bonding layer can hold the microdevice on top of the stacked EPE. The housing can have different shapes. In one case, the housing can match the shape of the device. The side wall of the housing can be shorter than the height of the micro device. The side wall of the housing can be connected to the micro device before the transfer cycle to provide support for different post-processing of the micro device.

During the transfer of the microdevices 2210 and 2212 from the donor substrate 2214 to the acceptor substrate, the EPE stack 2222 pushes the microdevice 2210 forward. This pushing force releases the anchor 2234, and the microdevice can be placed on the surface of the receptor substrate.

Figures 23A-23B show another embodiment of a microdevice on a donor substrate, wherein the microdevice can be selectively moved toward or away from the surface of the donor substrate.

In FIG. 23A, according to another embodiment, a stack of different materials 2304, 2308, 2310 with different thermal expansion coefficients is formed on the top of the donor substrate 2320 under the microdevices 2312, 2314, 2318, respectively. When the temperature of the stack 2308 changes, the stack 2308 becomes twisted and pushes the device 2314 further away from the surface of the donor substrate. In one case, applying current through the stack changes the temperature. Here, the electrodes 2302, 2306 can carry current. In another case, the light absorbing layer that is part of the stack converts light into thermal energy. In another case, the stack can resonate to a specific signal frequency such as microwave or ultrasonic. This resonance can increase the temperature or directly deform the stack.

FIG. 23B shows another example in which the structure of the micro devices 2312, 2314, 2318 on the top of the stacked layers 2304, 2308, 2310 is surrounded by a housing 2322. In addition, the anchors 2332, 2326 hold the devices 2312, 2314, and 2318 inside the housing structure. The anchor can be connected to the micro device or the housing. During the transfer of the device 2314 from the donor substrate 2320 to the acceptor substrate, the stack 2308 pushes the micro device 2314 forward. This pushing force releases the anchor 2326, and the microdevice 2314 can be placed on the surface of the receptor substrate.

Fig. 24 shows another example of a micro device on a donor substrate according to an embodiment of the present invention, wherein the micro device can be selectively moved toward or away from the surface of the donor substrate.

Here, the structure of the micro devices 2410, 2414, 2418 on the top of the stacked layer 2404 is surrounded by the housing 2422. In addition, anchors 2426, 2428 hold devices 2410, 2414, and 2418 inside the housing structure. During the transfer of the device 2414 from the donor substrate to the acceptor substrate, the electroactive polymer layer becomes a gas 2456, and the pressure generated by this change pushes the microdevice 2414 forward. The push/pull force releases the anchor 2426, and the microdevice 2414 can be placed on the surface of the receptor substrate. Thermal, optical, electrical, or chemical forces can change layer 2404 into a gas. In one case, the absorption layer 2458 can absorb light and heat the layer 2404-1 and generate gas pressure that pushes the microdevice forward. Micro device box structure

Some embodiments of the present invention also disclose methods for integrating the integrated micro device array into the system substrate or selectively transferring the micro device array to the system substrate.

According to one embodiment, a method for integrating a micro device on a backplane can be provided, which includes: providing a micro device substrate including one or more micro devices; by connecting the pads on the micro device and the corresponding solder on the backplane The disk bonds a group of selective micro-devices from the substrate to the back plate; and leaves the bonded selective micro-device group on the back plate by separating the micro-device substrate.

In one embodiment, a micro device array can be produced on a micro device substrate, where the micro device can be produced by etching one or more planar layers.

In another embodiment, one or more planarization layers may be formed on the microdevice substrate and cured by temperature, light or other sources.

In one embodiment, an intermediate substrate may be provided, wherein, in one case, one or more bonding layers may be formed on the intermediate substrate or on the planarization layer.

In another embodiment, the micro device substrate can be removed by laser or chemical peeling.

In one embodiment, there may be an opening in the buffer layer that connects the micro device to the planarization layer. In one case, the electrode may be provided on the top or bottom of the planarization layer.

In another embodiment, after removing the micro device substrate, additional processes may occur, such as removing an additional common layer, or thinning the planarization layer and/or the micro device.

In one case, more pads can be added to the micro device. The pads can be conductive or used purely for bonding to the system substrate. In one case, the buffer layer may connect at least one micro device to the test pad. The test pad can be used to bias the microdevice and test its functionality. Testing can be performed at the wafer level or at the intermediate (box) level. After the multiple layers are removed, the pads are accessible at the intermediate level.

In one case, the micro device may have more than one contact at the top side, and the buffer layer may be patterned to connect the contact of at least one of the micro devices to the test pad.

In one embodiment, a back plate may be provided. In one case, the backplane may have transistors and other elements for the pixel circuit to drive the micro device. In another case, the backplane may be a substrate without components.

In one embodiment, one or more pads may be provided on the backplane for the bonding process. In one case, the pads on the backplane or on the microdevice can create a force to pull out the microdevice.

After the micro device is transferred to the backplane, it is possible to detect the position/position of the micro device and adjust the patterning of other layers to match the alignment during the transfer process. In one case, different components can be used to detect the position of the micro device, such as a camera or a probe tip. In another case, the offset in the transfer setting can be used to identify the misalignment of the position of the micro device on the system substrate. In another case, the color filter or conversion layer can also be adjusted based on the position of the micro device. In one case, some random shifts in the microdevice position can be induced to reduce optical artifacts.

In one embodiment, the pattern of the microdevice can be modified (e.g., electrodes that couple the microdevice to a signal, a functionally tunable layer such as a color filter or color conversion, a through hole opened in the passivation/planarization layer, Or backplane layer).

In one case, the position/shape of the electrode can be modified based on the position of the microdevice. In another case, there may be some extensions of each electrode whose position or length may be modified based on the position of the microdevice.

Fig. 25A shows a cross-sectional view of a micro device array on a micro device substrate according to an embodiment of the present invention. Here, a micro device substrate 2502 is provided. The micro device array 2504 can be produced on the micro device substrate 2502. In one case, the micro device may be a micro LED. In another case, the micro device can be any micro device that is usually manufactured in a flat batch, including LEDs, OLEDs, sensors, solid state devices, integrated circuits, MEMS and/or other electronic components.

In one case, one or more planar active layers may be formed on the substrate. The planar active layer may include a first bottom conductive layer, a functional layer (for example, a light emitting layer), and a second top conductive layer. Microdevices can be produced by etching a planar active layer. In one case, the etching can reach the microdevice substrate all the way. In another case, there may be partial etching on the planar layer to leave some on the surface of the microdevice substrate. Other layers can be deposited and patterned before or after forming the microdevice.

FIG. 25B shows a cross-sectional view of a micro device array with a buffer layer according to an embodiment of the present invention. Here, the buffer layer 2506 may be formed on the micro device array 2504. The buffer layer 2506 may extend over the surface of the micro device substrate 2502. The buffer layer may be conductive. In one case, the buffer layer may be a patterned buffer layer. In another case, the buffer layer may be a common buffer layer. In one embodiment, the buffer layer 2506 may include electrodes that may be patterned or used as common electrodes.

FIG. 25C shows a cross-sectional view of a micro device array with a planarization layer according to an embodiment of the present invention. A planarization layer 2508 can be deposited on top of the micro device substrate 2502 around each micro device 2504. The planarization layer 2508 can be used for isolation and/or protection of micro devices. The planarization layer may include polymers such as polyamide, SU8, or BCB. The planarization layer can be cured. In one case, the planarization layer can be cured via temperature, light, or some other source.

FIG. 25D shows a cross-sectional view of a micro device array bonded to an intermediate substrate according to an embodiment of the present invention. In one embodiment, one or more bonding layers 2512 may be formed on the planarization layer 2508. The bonding layer 2512 may be the same or different from the planarization layer. In another case, a bonding layer may be formed on the top of the intermediate substrate (box) 2510. The bonding layer can provide one or more different forces such as electrostatic, chemical, physical, or thermal. The bonding layer 2512 may contact the planarization layer 2508. In order to form a contact between the planarization layer and the bonding layer, the bonding layer is cured by pressure, temperature, light or other sources.

In one embodiment, after the intermediate substrate 2510 is formed over the bonding layer, the micro device substrate 2502 can be removed, which can be performed by laser or chemical peeling.

In one case, there may be openings in the buffer layer 2506 that allow the microdevice 2504 to connect to the planarization layer 2508. This connection can act as an anchor. In one case, the buffer layer may be etched to form a housing, substrate, or anchor that at least partially surrounds each microdevice. After peeling off, the anchor can hold the microdevice to the substrate. In another case, the buffer layer may couple at least one of the micro device pads to the electrode. Electrodes can be placed on the top or bottom of the planarization layer.

Figure 25E shows a cross-sectional view of a micro device array with pads according to an embodiment of the present invention. The microdevice substrate can be removed to implement a flexible system or for post-processing steps performed on the side of the system facing the substrate. After removing the substrate, additional processes can be performed. These processes include one of the following: removing additional common layers or thinning the planarization layer and/or microdevices. In one case, one or more pads 2520 may be added to the microdevice 2504. In one case, these pads may be conductive. In another case, these pads are purely used for bonding to the system substrate. In one case, the buffer layer 2506 may be conductive.

In one embodiment, the buffer layer 2506 can connect one or more micro devices to the test pad. The test pad can be used to bias the microdevice and test its functionality. In one case, testing can be done at the wafer/substrate level. In another case, testing can be done at the middle (box) level. After the multiple layers are removed, the pads are accessible at the intermediate level.

In one case, if the micro device has more than one contact at the top side, the buffer layer can be patterned to connect the contact of at least one of the micro devices to the test pad.

Fig. 26 shows a cross-sectional view of a micro device array bonded to an intermediate substrate and a back plate according to an embodiment of the present invention. Here, a back plate 2630 can be provided. In one case, the TFT process can be used to manufacture the backplane. In another case, the backplane can be manufactured by using chiplets manufactured by complementary metal oxide semiconductor (CMOS) or other processes.

In one embodiment, the backplane may have transistors and other components for the pixel circuit to drive the micro device. In another embodiment, the backplane may be a substrate without components. One or more pads 2622 may be formed on the back plate 2630 to bond the back plate to the micro device array. In one case, the one or more pads on the backplane may be conductive.

In one embodiment, the buffer layer 2606 can be removed or deformed to release the microdevice. The pad 2622 on the backplane or the pad 2620 on the micro device can create a force to pull out the selected micro device 2640. In another embodiment, the buffer layer 2606 or the shell can be etched back, reduced or removed. The housing can be removed from the empty LED spot.

FIG. 27A shows the process steps of extracting the position of the micro device according to an embodiment of the present invention. After the micro device is transferred to the backplane, the position of the micro device on the backplane can be detected, and if there is misalignment during the transfer, the patterning of other layers can be adjusted to match the misalignment of the transfer. The process steps include: step 2702, placing the micro device on the system substrate; step 2704, using a camera, surface profiler (optical, ultrasonic, electrical) or other components to extract the position of the micro device on the system substrate; step 2706, possibly modifying A pattern of a micro device, where the pattern may include one of the following: electrodes that couple the micro device to a signal, a functionally tunable layer (such as color conversion or color filter), a through hole opened in the passivation/planarization layer, Or backplane layer. There may be a certain reference structure on the system substrate to first calibrate the tool used to extract the position of the micro device, or the reference may be used to find the relative position of the micro device.

In one embodiment, different components can detect the position of the micro device. For example, a camera, probe tip, surface profiler (optical, ultrasonic, electrical) or other components can detect/extract the position/positioning of the micro device. In another embodiment, the offset in the transfer setting can identify the misalignment of the position of the micro device on the system substrate/backplane.

For example, in one case, metallization patterning can avoid short circuits. In another case, the color filter or color conversion can also be adjusted based on the position of the micro device. This can reduce the tolerance required to place the microdevice. It is also possible to induce a certain random shift in the position of the micro device to reduce optical artifacts.

FIG. 27B illustrates modifying the position/shape of the electrode based on the position of the micro device according to an embodiment of the present invention. One or more microdevices 2710, 2712, or 2714 may have contact pads 2706. In one case, the position/shape of the electrodes 2702, 2704 may be modified based on the position of the microdevices 2710, 2712, 2714. In another case, the position/shape of the electrode may be modified based on the position of the through hole. In another case, the position of the through hole in the planarization/passivation layer can be modified according to the position of the micro device.

Figure 27C shows an extension provided to an electrode according to an embodiment of the present invention. In one case, the position of the electrode 2702 can be modified. And there may be a certain extension 2720 for each electrode, so that the position or length of the microdevice 2710, 2712, or 2714 can be modified based on the position of the microdevice 2710, 2712, or 2714. This can be used for common electrodes or individual electrodes.

According to an embodiment, a bonding structure may be provided. The bonding structure may include a plurality of micro-devices on the donor substrate, each micro-device including one or more conductive pads formed on the surface of the micro-device; and covering each micro-device or the one or more conductive solders Temporary material of at least a portion of the disc, wherein the temporary material is coupled to a current/voltage source to redirect current through the temporary material to the one or more conductive pads. The temporary material includes a conductive material or a non-conductive material, and the temporary conductive material further completely or partially covers the one or more conductive pads.

According to another embodiment, the method may further include a conductive layer at the donor substrate to couple the temporary conductive material to the current/voltage source; a housing structure to cover at least a part of each micro device on the donor substrate , Wherein the temporary material serves as an anchor for holding the plurality of micro-devices inside the housing structure in the donor substrate.

According to yet another embodiment, the method may further include at least one sacrificial layer between the housing structure and each micro device, wherein the temporary material is patterned to form an opening on the top surface of the donor substrate. The opening at the top surface of the donor substrate is used to release the micro device from the sidewall of the housing structure by removing the sacrificial layer. After the sacrificial layer is removed, the temporary material holds each micro device in place, and the sacrificial layer is removed by using a chemical etching process or electromagnetic signals.

According to other embodiments, the temporary material is separated from the housing structure after each micro-device is transferred to the receptor substrate by one of the following processes: mechanical process, optical process, thermal process, and chemical process. The conductive traces on the top surface of the donor substrate are connected as one of the following: net, column or row.

According to some embodiments, multiple access points on the top surface of the donor substrate are used to bias the temporary material via conductive traces. The temporary material forms a passage between the surface facing the donor substrate and the surface facing away from the donor substrate.

According to one embodiment, there is provided a method of bonding at least one microdevice to a receptor substrate. The method includes: forming a stack including an electrode and an electroactive polymer layer under the at least one microdevice on a donor substrate; A voltage is applied to the stack so that at least one microdevice is within the contact/proximity range of the surface of the receptor substrate.

According to some embodiments, the method may further include: providing a housing structure around the at least one micro-device; and providing an anchor to hold the at least one micro-device inside the housing structure.

According to another embodiment, the anchor releases the microdevice on the surface of the receptor substrate by one of pushing or pulling, the stack further includes an absorption layer that converts light into heat, and the electroactive polymer layer becomes a gas, And the pressure generated by the change pushes the at least one micro device to the surface of the receptor substrate.

According to one embodiment, a method for integrating a micro device on a backplane may be provided, including: forming a buffer layer on or above the one or more micro devices extending above a substrate; forming a planarization layer on the buffer layer, the The planarization layer includes a polymer, and wherein the polymer includes one of polyamide, SU8, or BCB; and a bonding layer is deposited between the planarization layer and the intermediate substrate.

According to another embodiment, the method may further include curing the bonding layer after contacting the planarization layer, and removing the micro device substrate by laser or chemical peeling. The bonding layer is cured by pressure, temperature or light.

According to another embodiment, the method may further include removing the micro device substrate by one of laser or chemical peeling, and wherein bonding a group of selective micro devices from the substrate to the back plate includes the following steps: aligning the micro devices The device and the backplate are brought into contact; the buffer layer is removed to release the microdevices; the force is formed to pull out the group of selected microdevices; and the group of selected microdevices is bonded to the backplate.

According to another embodiment, the method may further include providing an opening in the buffer layer to connect the micro device to the planarization layer. The buffer layer is conductive, wherein the buffer layer connects at least one micro device to the test pad.

According to another embodiment, the method may further include: providing an electrode on either the top or bottom of the planarization layer; coupling at least one microdevice to the electrode via a buffer layer; extracting the position of the microdevice on the backplane; and Extend the electrode position to the extraction position of the micro device on the backplane, where the position of the micro device is extracted by a camera, probe tip or surface profiler.

In summary, the present invention provides a micro device integration process that is transferred to a system substrate to complete, and electronic control integration. This transfer can be facilitated by various means, including providing temporary materials, breakable anchors on the donor substrate, or temporary intermediate substrates.

The foregoing description of one or more embodiments of the present invention has been presented for the purposes of illustration and description. The foregoing description is not intended to be exhaustive or to limit the invention to the precise form disclosed. In view of the above teachings, many modifications and changes are possible. It is intended that the scope of the present invention is not limited by this detailed description, but by the scope of the attached patent application.

110: Donor substrate 112: bottom plane or sheet conductive layer 114: functional layer 116: Top pixelated conductive layer 118: Current Distribution Layer 120: Dielectric layer 128: leveling layer 130: opening 132: Pad 150: system board 152: other layers 154: Pad 156: Dielectric layer 170: reflective layer or black matrix 210: Donor substrate 212: The first top plane or sheet conductive layer 214: functional layer 216: second bottom pixelated conductive layer 218: Current Distribution Layer 228: layer 232: Pad layer 250: system substrate 252: other layers 254: substrate pad 256: Dielectric layer 270: reflective layer or black matrix 310: Donor substrate 312: first bottom conductive layer 314: functional layer 316: second top conductive layer 332: Top contact 372: layer 372-2: Sacrifice Layer 374: Packing layer 376: Cassette (temporary) substrate 378: substrate bonding layer 380: Contact bonding layer 382: Pad 390: system board 412: first bottom conductive layer 414: functional layer 416: second top conductive layer 432: Top contact 472: MIS layer 474: Filling Material 476: Temporary Substrate 476-1: Anchor 476-2: Slot 478: substrate bonding layer 480: Lower contact pad 490: System (Receptor) Substrate 510: Donor substrate 512: first bottom conductive layer 514: functional layer 516: second top conductive layer 532: top contact pad 572: MIS layer 574: Packing layer 582: Pad 590: receptor substrate 592: layer 594: Extension 596: void/gap 598: Bridge 598-2: Possible release point 6110: Donor substrate 6112: device layer 6114: first buffer layer 6116: Separation layer 6118: second buffer layer 6150: substrate 6262: gap 6263: gap 6212: island 6210: Donor substrate 6220: Packing layer 1102: Microdevice 1104: micro device 1106: Microdevice 1108: box 1202: micro device 1204: micro device 1206: micro device 1206-2: other areas 1208: Multi-type micro device box 1302: micro device 1304: Donor substrate 1306: support layer 1308: support layer 1480: Donor substrate 1482: block 1483: block 1484: Crossover 1580: block 1582: block 1590: acceptor substrate 1680: block 1682: block 1684: block 1690: box 1790: box 1802: Donor substrate 1804: donor force component 1806: Stack 1812: voltage/current 1814: conductive pad 1816: conductive pad 1818: Receptor Force Element 1902: Donor substrate 1904: conductive/contact pad 1906: conductive/contact pad 1908: receptor substrate 1910: current/voltage 1912: Voltage/Current 1914: Voltage/Current 1918: Receptive Force Element 2002a: Temporary conductive materials 2002c: Temporary conductive materials 2002d: Temporary conductive material 2002e: Temporary conductive materials 2002f: conductive layer 2002g: Temporary conductive material 2002h: Conductive layer 2004a: conductive pad 2004c: conductive pad 2004d: conductive pad 2004e: pad 2004h: conductive material 2006a: Shell structure 2006b: shell 2006e: pad 2006c: conductive pad 2006d: conductive pad 2006h: conductive layer 2008a: sacrifice layer 2008b: sacrifice layer 2008c: sacrifice layer 2008e: sacrifice layer 2008f: conductive pad 2008g: conductive pad 2008h: conductive pad 2010a: Bonding materials 2010e: pad 2010f: conductive pad 2010g: conductive pad 2010h: conductive pad 2012g: conductive pad 2012h: conductive pad 2014a: anchor 2014g: conductive pad 2014h: conductive pad 2016: Microdevice 2102: Microdevice 2104: Donor substrate 2106: conductive pad 2106-1: conductive pad 2106-2: conductive pad 2106-3: conductive pad 2106-4: conductive pad 2108: Temporary conductive materials 2110: Temporary conductive materials 2204: Electrode 2206: Electrode 2208: Electroactive polymer (EPE) layer 2210: micro device 2212: micro device 2214: Donor substrate 2220: EPE 2222: EPE 2226: shell structure 2234: Anchor 2302: Electrode 2304: stacked layers 2306: Electrode 2308: stacked layers 2310: stacked layers 2312: micro device 2314: micro device 2318: micro device 2320: Donor substrate 2322: shell 2326: Anchor 2332: anchor 2404: stacked layers 2404-1: layer 2410: Microdevice 2414: Microdevice 2418: Microdevice 2422: shell 2426: anchor 2428: anchor 2456: Gas 2458: absorption layer 2502: Microdevice substrate 2504: micro device array 2506: buffer layer 2508: planarization layer 2510: Intermediate substrate 2512: Bonding layer 2520: pad 2606: buffer layer 2620: pad 2622: pad 2630: backplane 2640: micro device 2702: Electrode 2704: Electrode 2706: contact pad 2710: Microdevice 2712: Microdevice 2714: Microdevice 2720: Extension

The present invention will be described in more detail with reference to the accompanying drawings showing preferred embodiments of the present invention, in which:

Figure 1A shows a cross-sectional view of a lateral functional structure on a donor substrate according to an embodiment of the present invention;

1B shows a cross-sectional view of the lateral structure of FIG. 1A with a current distribution layer deposited thereon according to an embodiment of the present invention;

1C shows a cross-sectional view of the lateral structure of FIG. 1B after patterning the top dielectric conductive layer and depositing the second dielectric layer according to an embodiment of the present invention;

1D shows a cross-sectional view of the lateral structure after patterning the second dielectric layer according to an embodiment of the present invention;

1E shows a cross-sectional view of a lateral structure after pad deposition and patterning according to an embodiment of the present invention;

1F shows a cross-sectional view of a lateral structure after forming an integrated structure by bonding a bonding area to a system substrate according to an embodiment of the present invention;

1G shows a cross-sectional view of the integrated structure after removing the donor substrate and patterning the bottom electrode according to an embodiment of the present invention;

1H shows a cross-sectional view of the integrated structure after removing the donor substrate and patterning the bottom electrode according to an embodiment of the present invention;

2A shows a cross-sectional view of another embodiment of a lateral functional structure on a donor substrate with a pad layer;

2B shows a cross-sectional view of the lateral structure of FIG. 2A after patterning the pad layer, contact layer, and current distribution layer according to an embodiment of the present invention;

2C shows a cross-sectional view of the lateral structure of FIG. 2A after filling the distance between the patterned pads according to an embodiment of the present invention;

2D shows a cross-sectional view of the lateral structure of FIG. 2A aligned and bonded to the system substrate by patterned pads according to an embodiment of the present invention;

2E shows a cross-sectional view of the lateral structure of FIG. 2A with a device substrate removed according to an embodiment of the present invention;

3A shows a cross-sectional view of a mesa structure on a substrate of a device (donor) according to an embodiment of the present invention;

FIG. 3B shows a cross-sectional view of steps according to an embodiment of the present invention, in which empty spaces between the mesa structures of FIG. 3A are filled;

Figure 3C shows a cross-sectional view of the steps according to an embodiment of the present invention, in which the device (mesa structure) of Figure 3B is transferred to a temporary substrate;

3D shows a cross-sectional view of the steps according to an embodiment of the present invention, in which the device of FIG. 3C is aligned and bonded to the system substrate;

3E shows a cross-sectional view of the steps according to an embodiment of the present invention, in which the device is transferred to the system substrate;

Figure 3F shows the thermal profile of the thermal transfer step according to an embodiment of the present invention;

4A shows a cross-sectional view of a temporary substrate with a groove and a device transferred to it according to an embodiment of the present invention;

4B shows a cross-sectional view of the temporary substrate of FIG. 4A after cleaning the filler between the device space and the tank according to an embodiment of the present invention;

4C shows a cross-sectional view of a step according to an embodiment of the present invention, in which the device is transferred to the system substrate by breaking the released surface;

Figure 5A shows a cross-sectional view of a microdevice with different anchors in the filling layer according to an embodiment of the present invention;

5B shows a cross-sectional view of the microdevice after post-processing the filling layer according to an embodiment of the present invention;

5C shows a top view of the micro device of FIG. 5B according to an embodiment of the present invention;

5D shows a cross-sectional view of a transfer step for transferring a micro device to another substrate according to an embodiment of the present invention;

Figure 5E shows a cross-sectional view of transferring a micro device to a substrate according to an embodiment of the present invention;

6A shows a cross-sectional view of a mesa structure on a substrate of a device (donor) according to another embodiment of the present invention;

Figure 6B shows a cross-sectional view of the steps, in which empty spaces between the mesa structures of Figure 6A are filled;

Figure 6C shows a cross-sectional view of the steps according to an embodiment of the present invention, in which the device (mesa structure) of Figure 6B is transferred to a temporary substrate;

6D shows a cross-sectional view of the steps according to an embodiment of the present invention, in which a portion of the bottom conductive layer of FIG. 6C is removed;

Figure 6E shows a cross-sectional view of a microdevice with anchors in a filling layer according to an embodiment of the present invention;

Figure 6F shows a cross-sectional view of a microdevice with anchors in a filling layer according to an embodiment of the present invention;

Figure 6G shows a cross-sectional view of a microdevice with anchors in a filling layer according to an embodiment of the present invention;

Figure 6H shows a cross-sectional view of a preliminary step in another embodiment of the present invention;

FIG. 6I shows a cross-sectional view of the etching step in the embodiment of FIG. 6H according to an embodiment of the present invention;

6J shows a cross-sectional view of the separation step in the embodiment of FIG. 6H according to an embodiment of the present invention;

Figure 6K shows a top view of another embodiment of the present invention according to an embodiment of the present invention;

Figure 6L shows a cross-sectional view of the embodiment of Figure 6K according to an embodiment of the present invention;

Fig. 6M shows a cross-sectional view of the embodiment of Figs. 6K and 6L with filler material according to an embodiment of the present invention;

Figure 7 is a flowchart of the process of an embodiment of the present invention;

Figure 8 is a flowchart of a micro device installation process according to an embodiment of the present invention;

Figure 9 is a flowchart of a micro device installation process according to an embodiment of the present invention;

Figure 10 is a flowchart of a micro device installation process according to an embodiment of the present invention;

Figure 11 shows examples of donor or temporary (box) substrates with different types of pixelated microdevices according to embodiments of the present invention;

Figure 12 shows examples of donor or temporary (box) substrates with different types of pixelated microdevices according to embodiments of the present invention;

FIG. 13 shows an example of donor substrates used in the same type of microdevices but with different pitches between the microdevice groups according to an embodiment of the present invention;

FIG. 14A shows an example of a donor substrate or a temporary substrate with uneven output on a micro device block according to an embodiment of the present invention;

14B shows an example of a receptor substrate or system substrate with uneven output on a plurality of micro device blocks according to an embodiment of the present invention;

FIG. 14C shows an example of a system substrate with skewed microdevice blocks according to an embodiment of the present invention;

Figure 14D shows an example of a system substrate with flipped micro device blocks according to an embodiment of the present invention;

Figure 14E shows an example of a system substrate with flipped and alternating micro device blocks according to an embodiment of the present invention;

Figure 15A shows an example of a donor substrate with two different microdevice blocks according to an embodiment of the present invention;

FIG. 15B shows an example of a system substrate with deflection blocks of different microdevices according to an embodiment of the present invention;

Figure 16A shows an example of a donor substrate with three different types of pixelated microdevice blocks according to an embodiment of the present invention;

FIG. 16B shows an example of a system substrate having multiple different types of individual microdevices from each block according to an embodiment of the present invention;

FIG. 17A shows an example of a cassette substrate having multiple different types of pixelated microdevice blocks according to an embodiment of the present invention;

FIG. 17B shows an example of a cassette substrate with multiple different types of offset pixelated microdevice blocks according to an embodiment of the present invention;

FIG. 18 shows a donor substrate for holding a micro device via a donor force element according to an embodiment of the present invention.

Fig. 19 shows an example of a micro device having more than one contact pad on one side according to an embodiment of the present invention.

20A1-20A2 show examples of highlighting the temporary conductive material covering the microdevice according to some embodiments of the present invention.

20B1-20B2 show another example of highlighting the temporary conductive material covering the microdevice according to some embodiments of the present invention.

Figures 20C1-20C2 show another example of highlighting the temporary conductive material covering the microdevice according to some embodiments of the present invention.

Figures 20D-20H illustrate another example of highlighting a temporary conductive material covering a micro device according to some embodiments of the present invention.

20I1-20I2 show another example of highlighting the temporary conductive material covering the micro device according to some embodiments of the present invention.

Figure 21A shows an exemplary top view representation of Figure 20A according to an embodiment of the invention.

Figure 21B1 shows an exemplary top view representation of Figure 20B1 in accordance with an embodiment of the present invention.

Figure 21B2 shows another exemplary top view representation of Figure 20B2 in accordance with an embodiment of the present invention.

Figure 21C shows an exemplary top view representation of Figure 20E in accordance with an embodiment of the invention.

Figure 21D shows an exemplary top view representation of Figure 20F according to an embodiment of the invention.

22A-22C show a microdevice on a donor substrate according to an embodiment of the present invention, wherein the microdevice can be selectively moved toward or away from the surface of the donor substrate.

Figures 23A-23B illustrate a microdevice on a donor substrate according to an embodiment of the present invention, wherein the microdevice can be selectively moved toward or away from the surface of the donor substrate.

Fig. 24 shows another example of a micro device on a donor substrate according to an embodiment of the present invention, wherein the micro device can be selectively moved toward or away from the surface of the donor substrate.

Fig. 25A shows a cross-sectional view of a micro device array on a micro device substrate according to an embodiment of the present invention.

FIG. 25B shows a cross-sectional view of a micro device array with a patterned buffer layer according to an embodiment of the present invention.

FIG. 25C shows a cross-sectional view of a micro device array with a planarization layer according to an embodiment of the present invention.

FIG. 25D shows a cross-sectional view of a micro device array bonded to an intermediate substrate according to an embodiment of the present invention.

Figure 25E shows a cross-sectional view of a micro device array with pads according to an embodiment of the present invention.

Fig. 26 shows a cross-sectional view of a micro device array bonded to an intermediate substrate and a back plate according to an embodiment of the present invention.

FIG. 27A shows the process steps of extracting the position of the micro device according to an embodiment of the present invention.

FIG. 27B illustrates modifying the position/shape of the electrode based on the position of the micro device according to an embodiment of the present invention.

Figure 27C shows an extension provided to an electrode according to an embodiment of the present invention.

If the same reference signs are used in different drawings, similar or identical elements are indicated.

The present invention allows various modifications and alternative forms, and specific embodiments or implementations are shown as examples in the drawings and will be described in detail herein. However, the present invention is not limited to the specific form disclosed. In fact, the present invention covers all modifications, equivalents, and alternatives that fall within the spirit and scope of the present invention defined by the scope of the appended patent application.

110: Donor substrate

112: bottom plane or sheet conductive layer

114: functional layer

116: Top pixelated conductive layer

Claims (30)

A bonding structure, which includes: A plurality of micro-devices located on the donor substrate, each micro-device including one or more conductive pads formed on the surface of the micro-device; and A temporary material covering at least a portion of each microdevice or the one or more conductive pads, wherein the temporary material is coupled to a current/voltage source to redirect current through the temporary material to the one or more conductive pads. Such as the bonding structure of claim 1, wherein the temporary material includes a conductive material or a non-conductive material. Such as the bonding structure of claim 1, which further includes: A conductive layer located at the donor substrate, which couples the temporary conductive material to the current/voltage source. Such as the bonding structure of claim 2, wherein the temporary conductive material further completely or partially covers the one or more conductive pads. Such as the bonding structure of claim 1, which further includes: The housing structure covers at least a part of each micro device on the donor substrate. Such as the bonding structure of claim 5, wherein the temporary material serves as an anchor for holding the plurality of micro-devices inside the housing structure in the donor substrate. Such as the bonding structure of claim 1, which further includes: At least one sacrificial layer located between the housing structure and each micro device. The bonding structure of claim 1, wherein the temporary material is patterned to form an opening on the top surface of the donor substrate. The bonding structure of claim 8, wherein the opening at the top surface of the donor substrate is used to release the micro device from the sidewall of the housing structure by removing the sacrificial layer. Such as the bonding structure of claim 9, wherein the temporary material holds each micro device in place after removing the sacrificial layer, and wherein the sacrificial layer is removed by using a chemical etching process or electromagnetic signals. Such as the bonding structure of claim 8, wherein the temporary material is separated from the housing structure after each micro-device is transferred to the acceptor substrate by one of the following processes: mechanical process, optical process, thermal process, and chemical process. Such as the bonding structure of claim 11, wherein the conductive traces on the top surface of the donor substrate are connected as one of the following: a net, a column, or a row. The bonding structure of claim 11, wherein a plurality of access points on the top surface of the donor substrate are used to bias the temporary material via the conductive trace. Such as the bonding structure of claim 1, wherein the temporary material forms a passage between a surface facing the donor substrate and a surface facing away from the donor substrate. A method of placing at least one micro-device on a receptor substrate, the method comprising: Forming a stack including an electrode and an electroactive polymer layer under the at least one microdevice on the donor substrate; A voltage is applied to the stack to cause at least one microdevice to contact/adjacent the surface of the receptor substrate. Such as the method of claim 15, which further includes: Providing a housing structure around the at least one micro device; and An anchor is provided to hold the at least one micro device inside the housing structure. The method of claim 15, wherein the anchor releases the microdevice on the surface of the receptor substrate by one of pushing force or pulling force. The method of claim 15, wherein the stack further includes an absorbing layer that converts light into heat. The method of claim 15, wherein the electroactive polymer layer becomes a gas, and the pressure generated by the change pushes the at least one microdevice to the surface of the receptor substrate. A method for integrating a micro device on a backplane, the method comprising: Provide a micro device substrate including one or more micro devices; Bonding a group of selective micro devices from the substrate to the back board by connecting the contact pads on the micro devices and the corresponding pads on the back board; By separating the micro device substrate, the group of bonded selective micro devices is left on the backplane. Such as the method of claim 20, which further includes: Forming a buffer layer on or above the one or more micro devices extending above the substrate; Forming a planarization layer on the buffer layer, the planarization layer including a polymer, and wherein the polymer includes one of polyamide, SU8, or BCB; and A bonding layer is deposited between the planarization layer and the intermediate substrate. Such as the method of claim 21, which further includes The bonding layer is cured after contacting the planarization layer, wherein the bonding layer is cured by any of pressure, temperature, or light. Such as the method of claim 20, which further includes The micro device substrate is removed by one of laser or chemical peeling. Such as the method of claim 20, wherein the pads on the micro devices and the corresponding pads on the backplane are conductive. The method of claim 20, wherein bonding the group of selective microdevices from the substrate to the backplane includes the following steps: Aligning and contacting the micro devices with the back plate; Removing the buffer layer to release the micro devices; Generate a force to pull out the selected microdevices of the group; and Bond the selected microdevices of the group to the backplane. Such as the method of claim 20, which further includes Openings are provided in the buffer layer to allow the micro devices to be connected to the planarization layer. The method of claim 21, wherein the buffer layer is conductive. The method of claim 21, wherein the buffer layer connects at least one micro device to the test pad. Such as the method of claim 21, which further includes Providing electrodes on either the top or bottom of the planarization layer; and At least one micro device is coupled to the electrode via the buffer layer. Such as the method of claim 21, which further includes Extract the position of the micro device on the backplane; and The position of the electrode is extended to the extraction position of the micro device on the backplane, wherein the position of the micro device is extracted by one of a camera, a probe tip or a surface profiler.

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