High throughput microreplication process

Abstract

Embodiments disclose methods of transferring selected micro devices on a receiver substrate. In one embodiment, a high resolution display containing an array of light emitting devices (LEDs) can be provided to assist in transferring the micro devices. The array of LEDs can selectively release a layer of adhesive or cure a bonding layer using light. Pixels in the display can be turned on at a predefined intensity corresponding to a group of selected micro devices to release the group of selected micro devices from a donor substrate.

Description

Technical Field

[0001] The present invention relates to integrating microdevices into a recipient substrate, and more particularly, to structures and methods for assisting in the transfer of selective microdevices from a donor substrate to a recipient substrate. Summary of the Invention

[0002] One objective of the present invention is to provide a method and structure for transferring and bonding selective microdevices from a donor substrate to a recipient substrate.

[0003] According to one embodiment, a method for transferring selected microdevices on a acceptor substrate is provided. A high-resolution display comprising an array of light-emitting devices (LEDs) can be provided to assist in the transfer of the microdevices. The LED array can selectively release or cure a bonding layer by using light. A selected group of LEDs in the LED array can be turned on. Therefore, release or curing can be selectively performed. If the release or curing layer is attached to the LED / microdevice, then the microdevice will be released or cured onto the acceptor substrate.

[0004] According to another embodiment, a housing structure / film coupled to an LED array can be provided. A pair of microdevices are connected to the housing via a release layer. A light guide or light confinement structure can be used to directly focus the light from each LED / pixel onto the surface of the housing or microdevice, thereby reducing light diffusion to adjacent microdevices. The LED array can have a higher resolution than the microdevices embedded in the housing structure / film. The housing can be a polymer or other material or different layers. The housing can also absorb light from the LEDs to further reduce light leakage to neighboring / adjacent microdevices.

[0005] According to one embodiment, a microdevice coupled to an LED array is moved near a acceptor substrate. The acceptor substrate may have a bonding or holding layer on top. The layer may be patterned or uniform. The bonding / holding layer may be conductive. After an alignment process, the microdevice and acceptor substrate are moved closer together such that the microdevice is partially (or completely) in contact with the holding / bonding layer. The LED is selectively turned on. In this case, a release layer associated with a selected microdevice is released or a portion of the bonding / holding layer associated with the selected microdevice is solidified. Thus, the selected microdevice remains on the acceptor substrate.

[0006] According to another embodiment, a method for transferring selected microdevices to a recipient substrate is provided. The method includes: providing one or more microdevices on a donor substrate, wherein a portion of each microdevice is coupled to a housing film via a release layer; providing a holding layer coupled to a recipient substrate; providing a display coupled to the donor substrate; aligning the microdevices with the recipient substrate; moving the microdevices or the recipient substrate to a predefined position; activating pixels in the display corresponding to a selected group of microdevices at a predefined intensity to release the selected group of microdevices from the donor substrate; holding the selected group of microdevices on the recipient substrate having the holding layer; and separating the recipient substrate from the housing film, leaving the selected group of microdevices on the recipient substrate.

[0007] According to one embodiment, the release layer may include a layer that converts light into heat to induce ablation and pushes the microdevice toward the acceptor substrate away from the housing. In one case, the housing film may also be the release layer. In another case, the substrate may be the release layer.

[0008] Given the detailed description of various embodiments and / or aspects with reference to the drawings, the foregoing and additional aspects of the invention and embodiments will be apparent to those skilled in the art, and a brief description of the drawings is provided below. Attached Figure Description

[0009] The foregoing and other advantages of the present invention will become apparent after reading the following detailed description and referring to the drawings.

[0010] Figure 1A A cross-sectional view of a donor substrate having an array of microdevices bonded to a temporary substrate is shown according to an embodiment of the present invention.

[0011] Figure 1B A cross-sectional view showing the removal of the donor substrate according to an embodiment of the present invention is shown.

[0012] Figure 1C A cross-sectional view showing the alignment of a temporary substrate with a display according to an embodiment of the present invention is shown.

[0013] Figure 2A A cross-sectional view showing the selective transfer of a microdevice into a receptor substrate using a display, according to an embodiment of the invention.

[0014] Figure 2B A cross-sectional view of the selected microdevice being activated according to an embodiment of the present invention is shown.

[0015] Figure 2C A cross-sectional view of a force-driven element according to an embodiment of the present invention is shown.

[0016] Figure 2DA cross-sectional view showing the transfer of another set of selective microdevices into a receptor substrate using a display according to an embodiment of the invention is illustrated.

[0017] Figure 2E A cross-sectional view showing the activation of another set of selective microdevices according to an embodiment of the present invention is shown.

[0018] Figure 2F A cross-sectional view is shown illustrating the use of a pushing force element to further embed another set of microdevices to be transferred into a retaining layer according to an embodiment of the invention.

[0019] Figure 3A Another cross-sectional view is shown illustrating the use of global forces to transfer a microdevice from a thin film into a receptor substrate according to an embodiment of the invention.

[0020] Figure 3B A cross-sectional view showing the transfer of a microdevice from a thin film to a receptor substrate using global force according to an embodiment of the invention.

[0021] Figure 3C A cross-sectional view is shown illustrating the use of a pushing force element to further embed the microdevice to be transferred into a retaining layer according to an embodiment of the invention.

[0022] Figure 3D A cross-sectional view showing the transfer of another set of selective microdevices into a receptor substrate according to an embodiment of the present invention is shown.

[0023] Figure 3E A cross-sectional view showing the activation of another set of selective microdevices according to an embodiment of the present invention is shown.

[0024] Figure 3F A cross-sectional view is shown illustrating the use of a pushing force element to further embed another set of microdevices to be transferred into a retaining layer according to an embodiment of the invention.

[0025] Using the same reference numerals in different diagrams indicates similar or identical elements.

[0026] Given the detailed description of various embodiments and / or aspects with reference to the drawings, the foregoing and additional aspects of the invention and embodiments will be apparent to those skilled in the art, and a brief description of the drawings is provided below. Detailed Implementation

[0027] While the invention allows for various modifications and substitutions, specific embodiments or implementations are illustrated by way of examples in the drawings and will be described in detail herein. However, it should be understood that the invention is not intended to be limited to the specific forms disclosed. Rather, the invention covers all modifications, equivalents, and alternatives that fall within the spirit of the invention as defined by the appended claims.

[0028] Unless the context clearly indicates otherwise, as used in this specification and claims, the singular forms “a / an” and “the” include a plurality of references.

[0029] In this specification, the terms "system substrate," "receiver substrate," and "display substrate" are used interchangeably. However, those skilled in the art will understand that the embodiments described herein are independent of substrate type.

[0030] In this specification, the terms "donor substrate" and "carrier substrate" are used interchangeably. However, those skilled in the art will understand that the embodiments described herein are independent of substrate type.

[0031] In this specification, the terms "temporary substrate," "intermediate substrate," and "cassette substrate" are used interchangeably. However, those skilled in the art will understand that the embodiments described herein are independent of substrate type.

[0032] Furthermore, these embodiments illustratively show five micro-light-emitting devices, but the invention is not limited thereto. The number of micro-light-emitting devices can be varied according to actual needs.

[0033] Many microdevices, including light-emitting diodes (LEDs), organic LEDs, sensors, solid-state devices, integrated circuits, MEMS (microelectromechanical systems), and other electronic components, are typically manufactured in batches (usually on planar substrates). To form an operating system, microdevices from at least one donor substrate need to be selectively transferred to an acceptor substrate.

[0034] Some embodiments of the present invention may include exemplary methods of forming a microdevice coupled to a housing thin film on a donor substrate and coupling the donor substrate to a display. The display has a resolution higher than that of the microdevice on the donor substrate.

[0035] Figure 1A A cross-sectional view of a donor substrate having an array of microdevices bonded to a temporary substrate is shown according to an embodiment of the invention. Here, one or more microdevices 102 are fully or partially formed on an untreated (or temporary) substrate 104. Subsequently, at least a portion of the microdevices 102 is covered by a release layer 106. Subsequently, a shell film / structure 108 is formed on or around the microdevices 102. The shell may be a polymer or other material or a different layer. The shell may also absorb light from the LED to further reduce light leakage to adjacent / adjacent microdevices. In one case, this method may be performed after the microdevices have been transferred to another temporary substrate 110.

[0036] Figure 1BA cross-sectional view of the removal of the donor substrate according to an embodiment of the invention is shown. The housing structure 108 is then bonded to another temporary substrate 110 to assist the peeling process. In one case, the microdevice housing film 108 remains on the untreated substrate despite the peeling process. In another case, the housing film 108 is transferred to the temporary substrate 110. Further processing steps, such as adding a contact layer, can be performed after peeling.

[0037] Figure 1C A cross-sectional view showing the alignment of a temporary substrate with an LED array according to an embodiment of the present invention is shown. Microdevices 102 embedded in the housing film 108 can be detached from the temporary substrate.

[0038] Here, the display 120 can be aligned and coupled to the microdevice housing film 108 directly or via the light guide structure 122. The light guide or light confinement structure 122 can be used to focus the light from each LED / pixel directly onto the surface of the housing film or microdevice, thereby reducing light diffusion to adjacent microdevices. In one case, the temporary substrate 110 can be removed (e.g., Figure 1B (As shown in the diagram) to minimize the distance between the microdevice and the display. In another case, a temporary substrate can be aligned with the display.

[0039] The display 120 may be an LED array 124 or a light modulation device with a back (or front) light source. This description is based on an LED array; however, this description can also be applied to light modulation devices.

[0040] In one scenario, the display 120 can be replaced with an array of heaters or mechanical actuators that can be selectively activated. Heat can alter the properties of the release layer 106 and thus affect the force between the microdevice 102 and the housing membrane 108. The mechanical actuators can push the microdevice 102 away from the housing membrane 108 or cause the release layer 106 to disintegrate.

[0041] In another case, the LED array 124 may be part of the pickup head. Here, the pickup force may be part of the array or at the edge of the LED array 124.

[0042] In another configuration, the LED array 124 is coupled to the microdevice housing film 108. The assembly is then picked up by a pickup head. Here, after alignment, the LED array 124 is bonded to the microdevice film (or housing), the pickup head picks up the assembly, and the LED array is connected to a controller that determines which LEDs are turned on. This connection can be part of the pickup process and the pickup force. The pickup head can use one of the following: vacuum force, electrostatic force, electromagnetic force, or another type.

[0043] In another scenario, the microdevice thin film or composite structure is assembled in a holder or template that can provide a acceptor substrate. When using a holder or template for the microdevice thin film, the display (LED array) can be another array from the microdevice housing thin film and projected onto the housing thin film to selectively release the device.

[0044] Figures 2A-2F A cross-sectional view illustrating the selective transfer of microdevices into a receptor substrate using an LED array according to an embodiment of the present invention.

[0045] Figure 2A This demonstrates a process for selectively transferring microdevices onto a recipient substrate using an LED array. A recipient substrate 202 with a holding layer 204 is provided. A microdevice housing film 108 is aligned with the recipient substrate 202. Here, an LED array 120 can be used as part of the alignment process. A set of different or identical LEDs 206 at low intensities are turned on as alignment markers. The alignment system uses the alignment markers on the recipient substrate 202 and the LED array 206 with the microdevice housing film 108 to align the two structures. This method can be repeated once, and subsequently using calibrated data calls to move the microdevice housing film to different locations on the recipient substrate 202, or the method can be repeated multiple times.

[0046] After the microdevice housing film 108 is moved to a predefined position, the housing film or the acceptor substrate 202 is moved toward each other so that the microdevice 102 touches the acceptor substrate 202. Here, additional force can be used to press the microdevice against the acceptor substrate 202.

[0047] Figure 2B A cross-sectional view of a selectively activated microdevice according to an embodiment of the invention is shown. An LED 206 associated with the selected microdevice 208 is activated at a predefined intensity. Light (wavelength) can be released from or cured at the interface between the microdevice 208 and the acceptor substrate 202 from the release layer 106. The acceptor substrate 202 is separated from the microdevice housing film 108, and the selected microdevice 208 remains on the acceptor substrate 202 embedded in the retaining layer 204.

[0048] Figure 2C A cross-sectional view is shown of a driving element for further embedding a microdevice to be transferred in a holding layer 204 according to an embodiment of the invention. This is after the microdevice has been transferred into a receiver substrate (e.g., Figure 2BAs shown in the diagram, a pushing force element 212 can be used to further embed the microdevice 208 to be transferred into the holding layer 204. The holding layer can be patterned or uniform. The bonding / holding layer can be conductive. Here, the holding layer 204 can be thicker than or the same height as the microdevice 208. The holding layer 204 can have different layers to accommodate different functions. The pushing force 212 can be generated by a stronger extraction force, or a mechanical setting that presses the microdevice into the holding layer. Here, the mechanical setting can have a surface profile that allows the microdevice to penetrate deeper into the holding layer 204.

[0049] Figure 2D-2F A cross-sectional view is shown illustrating the transfer of another set of selective microdevices into a acceptor substrate according to an embodiment of the invention. The surface after the first set of microdevices is embedded in the retaining layer is almost flat again. This allows for the transfer of a second (and more) type of microdevice using different microdevice films. A similar method can be repeated for the second and other types of microdevices.

[0050] Figure 2D A cross-sectional view of another set of selected microdevices activated according to an embodiment of the invention is shown. Here, the LED 206-2 associated with the selected microdevice 208-2 is turned on at a predefined intensity. The lamp (wavelength) can release the microdevice 208-2 from the release layer 106 or solidify the interface between the microdevice 208-2 and the acceptor substrate 202.

[0051] Figure 2E The receptor substrate 202 is separated from the microdevice housing film 108, and the selected microdevice 208-2 remains on the receptor substrate 202 embedded in the retaining layer 204.

[0052] Figure 2F A cross-sectional view is shown for a driving force element for further embedding another set of microdevices to be transferred in a holding layer according to an embodiment of the invention. This is after the microdevices have been transferred to the acceptor substrate (e.g., Figure 2E As shown in the diagram, a pushing force element 212 can be used to further embed the microdevice 208-2 to be transferred into the holding layer 204. Here, the holding layer 204 may be thicker than or the same height as the microdevice 208-2. The holding layer 204 may have different layers to accommodate different functions. The pushing force 212 may be generated by a stronger extraction force or by a mechanical setting that presses the microdevice 208-2 into the holding layer. Here, the mechanical setting may have a surface profile that allows the microdevice to penetrate deeper into the holding layer 204.

[0053] Some embodiments of the present invention involve transferring a microdevice from a housing thin film into a receiver substrate using a global force applied to the receiver substrate. The global force removes the microdevice after the release layer weakens. The global removal force can be an electromagnetic force or an electrostatic force.

[0054] Figures 3A-3C Another cross-sectional view is shown illustrating the use of global force to transfer a microdevice from a housing film into a receptor substrate according to an embodiment of the invention.

[0055] Here, the global force 302 removes the microdevice 102 toward the acceptor substrate 202, while the release layer 106 holds the microdevice in place on the housing film 108. By activating the LED 304 associated with the selected microdevice 102 in the display 306, the release layer 106 is weakened and the microdevice 102 is removed toward the acceptor substrate 202.

[0056] In one case, the same or different light in the LED array 306 can be used to solidify the interface between the microdevice and the acceptor substrate 202 to permanently hold it in place.

[0057] The global extraction force 302 can be either electromagnetic or electrostatic. In the case of an electromagnetic force, the microdevice is magnetic. Here, the magnetic force beneath the acceptor substrate extracts the microdevice towards the acceptor substrate. However, the release layer holds it in place. For samples with a weakened release layer, the microdevice moves towards the acceptor substrate. In the case of an electrostatic force, the microdevice is charged or biased, and the global electrode beneath the acceptor substrate (or on top of the acceptor substrate or as part of the acceptor substrate) attracts the microdevice. Here, the microdevice can be selectively biased or charged for further selective enhancement. Samples with a weakened release layer 106 will move towards the acceptor substrate 202.

[0058] Figure 3B A cross-sectional view showing the transfer of a microdevice from a thin film to a receptor substrate using global force according to an embodiment of the invention.

[0059] Here, a receptor substrate 202 with a holding layer 204 is provided. A microdevice housing film 108 is aligned with the receptor substrate 202. Here, an LED array 306 can be used as part of the alignment process. A set of different or identical LEDs at low intensities of 304 are turned on as alignment marks. The alignment system uses the alignment marks on the receptor substrate 202 and the LED array 306 with the microdevice housing film 108 to align the two structures. This method can be repeated once, and subsequently using calibrated data to move the microdevice housing film to different positions on the receptor substrate 202, or the method can be repeated multiple times.

[0060] After the microdevice housing film 108 moves to a predefined position, the housing film or the acceptor substrate 202 moves toward each other, causing the microdevice to touch the acceptor substrate 202. A global force 302 removes the selected microdevice 308 toward the acceptor substrate 202, while the release layer 106 holds the microdevice in place on the housing film 108. The release layer 106 is weakened by activating the LED 304 associated with the selected microdevice 308 in the display 306, thus removing the microdevice 308 toward the acceptor substrate 202.

[0061] To avoid tilting or misalignment, a predefined position is chosen for the microdevice's thin-film housing (donor substrate) relative to the acceptor substrate, such that the microdevice, moved to the acceptor substrate by a take-off force, is still partially supplied through the housing film. This distance is based on the depth of the housing film and the height of the microdevice. After the microdevice is temporarily or completely secured, the donor substrate can be removed from the acceptor substrate, and thus the microdevice is completely detached from the housing film.

[0062] Figure 3C A cross-sectional view is shown for a driving force element for further embedding a microdevice to be transferred in a holding layer according to an embodiment of the invention. This is after the microdevice has been transferred into a receiver substrate (e.g., Figure 3B As shown in the diagram, the transferred microdevice 308 can be further embedded in the holding layer 204 using a pushing force element 312. Here, the holding layer 204 may be thicker than or the same height as the microdevice 208. The holding layer 204 may have different layers to accommodate different functions. The pushing force 312 may be generated by a stronger extraction force, or a mechanical device that presses the microdevice into the holding layer. Here, the mechanical device may have a surface profile that allows the microdevice to penetrate deeper into the holding layer 204.

[0063] Figure 3D A cross-sectional view is shown illustrating the transfer of another set of selective microdevices into a receptor substrate according to an embodiment of the invention. Here, another set of LEDs 304-2 associated with the selected microdevice 308-2 is turned on at a predefined intensity. By turning on the LEDs 304-2 associated with the selected microdevice 308-2 in the display 306, the release layer 106 is weakened, and thus the microdevice 308-2 is removed toward the receptor substrate 202 using a global force 302.

[0064] Figure 3EThe acceptor substrate 202 is separated from the microdevice housing film 108, with the selected microdevice 308-2 remaining embedded in the retaining layer 204 on the acceptor substrate 202. The microdevice 308-2, moved to the acceptor substrate by a global force 302, is still partially supported by the housing film 108. This distance is based on the depth of the housing film and the height of the microdevice. After the microdevice 308-2 is temporarily or completely secured, the donor substrate can be removed from the acceptor substrate, and thus the microdevice is completely detached from the housing film.

[0065] Figure 3F A cross-sectional view is shown for further embedding a propulsion element in a holding layer for another set of transferred microdevices according to an embodiment of the invention. This is after the microdevices have been transferred into the acceptor substrate (e.g., Figure 3E As shown, the transferred microdevice 308-2 can be further embedded in the holding layer 204 using a pushing force element 312. Here, the holding layer 204 may be thicker than or the same height as the microdevice 308-2. The holding layer 204 may have different layers to accommodate different functions. The pushing force 312 may be generated by a stronger extraction force or by a mechanical setting that presses the microdevice 308-2 into the holding layer. Here, the mechanical setting may have a surface profile that allows the microdevice to penetrate deeper into the holding layer 204.

[0066] In the foregoing embodiments, the release layer may include a layer that converts light into heat to induce ablation and pushes the microdevice toward the acceptor substrate away from the housing.

[0067] According to another embodiment, a method for transferring selected microdevices to a recipient substrate is provided. The method includes: providing one or more microdevices on a donor substrate, wherein a portion of each microdevice is coupled to a housing film via a release layer; providing a holding layer coupled to a recipient substrate; providing a display coupled to the donor substrate; aligning the microdevices with the recipient substrate; moving the microdevices or the recipient substrate to a predefined position; activating pixels in the display corresponding to a selected group of microdevices at a predefined intensity to release the selected group of microdevices from the donor substrate; holding the selected group of microdevices on the recipient substrate having the holding layer; and separating the recipient substrate from the housing film, leaving the selected group of microdevices on the recipient substrate.

[0068] According to some embodiments, the retaining layer provides temporary bonding to remove the selected microdevice assembly from the donor substrate after the release layer weakens. After the microdevice is placed on or within the retaining layer, the retaining layer is cured to provide permanent bonding.

[0069] According to other embodiments, the method may further include providing a driving force element to cause the selected microdevice assembly being transferred to penetrate deeper into the retaining layer.

[0070] According to another embodiment, the method may further include: activating a second group of pixels in the display corresponding to a second group of selected microdevices at a predefined intensity to release the second group of selected microdevices from the donor substrate; holding the second group of selected microdevices on a recipient substrate having a holding layer; and separating the recipient substrate from the housing film, thereby leaving the second group of selected microdevices on the recipient substrate.

[0071] According to one embodiment, the method may further include providing a global force by weakening the release layer to remove the microdevice toward the acceptor substrate. The global force may include one of the following: an electromagnetic force or an electrostatic force. When an electrostatic force is applied to the acceptor substrate, the microdevice is charged or biased, and a global electrode beneath the acceptor substrate attracts the microdevice.

[0072] According to another embodiment, the step of activating pixels in the display corresponding to a selected group of microdevices with a predefined intensity further includes solidifying a portion of a retaining layer associated with the selected group of microdevices.

[0073] According to one embodiment, the holding layer is a single or patterned layer. The display includes an array of light-emitting diodes or an optical modulation device. The display has a higher resolution than the donor microdevice array.

[0074] According to one embodiment, the method may further include providing a light guide or light confinement structure above the display to directly focus the light from each pixel onto the surface of the housing film. The housing film comprises a polymer.

[0075] According to another embodiment, providing a display coupled to a donor substrate includes aligning the donor substrate directly or via a light guide structure with the display. After alignment, the display is bonded to the donor substrate. The display has a pickup force capable of picking up the donor substrate.

[0076] According to other embodiments, a donor substrate is placed in a template, wherein the template may hold one or more donor substrates during the transfer process. A display is projected onto the donor substrate to weaken the release layer for a selected microdevice. The display may include an array of heaters or mechanical actuators.

[0077] In the foregoing embodiments, the release layer may include a layer that converts light into heat to induce ablation and pushes the microdevice toward the acceptor substrate away from the housing.

[0078] In one embodiment, the outer shell film may also be a release layer. In another embodiment, the substrate may be a release layer.

[0079] While the invention allows for various modifications and substitutions, specific embodiments or implementations have been shown by way of examples in the drawings and described in detail herein. However, it should be understood that the invention is not intended to be limited to the specific forms disclosed. Rather, the invention is intended to cover all modifications, equivalents, and alternatives that fall within the spirit and scope of the invention as defined by the appended claims.

Claims

1. A method for transferring a selected microdevice to a acceptor substrate, the method comprising: One or more microdevices are provided on a donor substrate, wherein a portion of each microdevice is coupled to a housing film via a release layer; Provide a holding layer coupled to the receptor substrate; Provide a display coupled to the donor substrate; Align the microdevice with the receptor substrate; Move the microdevice or the receptor substrate to a predefined position; A pixel in the display corresponding to a selected group of microdevices is activated with a predefined intensity to release the selected group of microdevices from the donor substrate. The selected microdevice assembly is held on the holding layer coupled to the receptor substrate; as well as Separate the acceptor substrate from the donor substrate, leaving the selected microdevice assembly on the acceptor substrate.

2. The method of claim 1, wherein the retaining layer provides a temporary bond to remove the selected microdevice assembly from the donor substrate after the release layer has weakened.

3. The method of claim 1, wherein the retaining layer is cured to provide a permanent bond after the microdevice is placed on or inside the retaining layer.

4. The method of claim 1, further comprising: A driving force element is provided to allow the selected microdevice assembly to penetrate deeper into the retaining layer.

5. The method of claim 1, further comprising: A second group of pixels in the display corresponding to a second group of selected microdevices is activated with a predefined intensity to release the second group of selected microdevices from the donor substrate. The second group of selected microdevices are held on the receptor substrate having the holding layer; as well as Separate the receptor substrate from the outer shell film, leaving the second set of selected microdevices on the receptor substrate.

6. The method of claim 1, further comprising: A global force is provided by weakening the release layer to extract the microdevice toward the receptor substrate.

7. The method of claim 6, wherein the global force comprises one of the following: electromagnetic force or electrostatic force.

8. The method of claim 7, wherein when the electrostatic force is applied to the receptor substrate, the microdevice is charged or biased and the global electrode beneath the receptor substrate attracts the microdevice.

9. The method of claim 1, wherein the step of activating pixels in the display corresponding to a selected group of microdevices with a predefined intensity further comprises solidifying a portion of the retaining layer associated with the selected group of microdevices.

10. The method of claim 1, wherein the retaining layer is a patterned layer.

11. The method of claim 1, wherein the display comprises an array of light-emitting diodes or a light modulation device.

12. The method of claim 1, wherein the display has a higher resolution than the microdevice on the donor substrate.

13. The method of claim 1, further comprising: A light guide structure or light confinement structure is provided above the display to focus the light from each pixel directly onto the surface of the outer shell film.

14. The method of claim 1, wherein the outer shell film comprises a polymer.

15. The method of claim 13, wherein providing a display coupled to the donor substrate comprises: The donor substrate is aligned with the display directly or via the light guide structure.

16. The method of claim 15, wherein the display is bonded to the donor substrate after alignment.

17. The method of claim 1, wherein the display has a pickup force for picking up the donor substrate.

18. The method of claim 1, wherein the donor substrate is placed in a template, wherein the template holds one or more donor substrates during the transfer of the selected microdevice to the recipient substrate.

19. The method of claim 15, wherein the display is projected onto the donor substrate to weaken the release layer for the selected microdevice.

20. The method of claim 15, wherein the display comprises an array of heating or mechanical actuators.

21. The method of claim 1, wherein the outer shell film partially supports the selected microdevice on the receptor substrate.

22. The method of claim 1, wherein the release layer comprises a layer that converts light into heat to induce ablation and pushes the microdevice toward the receptor substrate away from the housing.

Images