Integrated color conversion cartridge

Abstract

This invention discloses the formation of a microdevice having an optical structure on a substrate. Specifically, it discloses microdevices having sidewalls, a top side, and a bottom side, as well as methods for forming a housing or cavity using different processes. These processes utilize protective layers, patterning and passivation, and alignment techniques.

Description

Technical Field

[0001] This disclosure relates to the integration of microdevices into system substrates. Summary of the Invention

[0002] According to one embodiment, an inventive method for forming a microdevice with an optical structure on a substrate includes: holding the microdevice on the top of the substrate, wherein the microdevice has a top side, a bottom side, and a sidewall different from the bottom side and the top side, and the top side faces away from the substrate; forming an optical layer on the top side of the microdevice; forming a passivation layer on top of the optical layer; and transferring the microdevice and the optical layer into a system substrate.

[0003] According to another embodiment, the present invention discloses a method for forming a microdevice having an optical structure on a substrate. The method includes: holding the microdevice on a first bonding layer on top of the substrate; covering the microdevice with a first layer; covering the microdevice with a protective layer; forming an optical layer aligned with the microdevice on top of the first bonding layer; and forming a passivation layer on top of the optical layer such that the passivation layer also covers the sidewalls of the microdevice.

[0004] According to another embodiment, the present invention discloses a method for integrating a microdevice with an optical structure, the method comprising: covering the microdevice with a protective layer; extending a portion of the protective layer to form a housing; and securing the optical layer within the housing. Simple Explanation of the Diagram

[0005] The advantages of this disclosure will become apparent after reading the following embodiments and referring to the drawings.

[0006] Figure 1A illustrates a method for forming a microdevice with an optical structure on a donor substrate.

[0007] Figure 1B shows the device undergoing back etching to form the outer shell structure.

[0008] Figure 1C shows the patterned release layer.

[0009] Figure 1D shows that after forming a layer on top of the optical structure, a bonding layer is used to bond the substrate to the top surface.

[0010] Figure 1E shows the removable temporary substrate.

[0011] Figures 2A and 2B illustrate another related embodiment in which there are no layers between the devices.

[0012] Figure 2C shows the release layer formed below the device.

[0013] Figure 2D shows that an anchoring layer is also formed below the device and the release layer.

[0014] Figure 3A shows an exemplary embodiment of a microdevice with an optical layer integrated into the device.

[0015] Figure 3B shows an example of integrating the device of Figure 3A into the receiver substrate.

[0016] Figure 3C shows an example of integrating the device of Figure 3A into the receiver substrate.

[0017] This disclosure is susceptible to various modifications and alternatives, and specific embodiments or implementations have been illustrated in the drawings and will be described in detail herein. However, it should be understood that this disclosure is not intended to limit it to the specific forms disclosed. Rather, this disclosure will cover all modifications, equivalents, and alternatives that fall within the spirit and scope of the invention as defined by the appended claims. Implementation

[0018] In this specification, the terms "device" and "microdevice" are used interchangeably. However, it will be apparent to those skilled in the art that the embodiments described herein are independent of device size.

[0019] The following description describes methods and structures for the generation of microdevices and / or their integration with optical structures. There is no additional need or separate description of methodologies, and this description can be interpreted as equivalent to the combination of descriptions of structure, material details, and various processes used in the claimed method.

[0020] The microdevices on the donor substrate have a top surface away from the substrate and a bottom surface facing the substrate. At least a portion of the top or bottom surface of the microdevice is covered by an optical layer (e.g., a color conversion material or a lens). A layer holds the bottom side of the microdevice to the donor substrate. This layer may be an adhesive or an anchor. A release layer may be present between the holding layer and the substrate. An optical coupling or encapsulation layer may be present between the device and the optical layer. A protective layer may be present covering at least one other side of the device not covered by the color conversion layer. The protective layer may extend along the edge of the surface covered by the optical layer to accommodate at least a portion of the optical layer. The protective layer may be reflective to guide light to the optical layer. In one related case, the device in the donor substrate may have more than one type of optical layer. In another related case, different devices may have different optical layers. For example, one device may have a green conversion layer, while another device may have a red conversion layer. These devices are transferred to a recipient substrate to form a microdevice array. Optical layers can provide various functionalities within a device, such as color conversion, directing input or output light in a specific direction, or modifying light distribution. Microdevices may have pads on the top, bottom, or other sides. These pads provide electrical connections to the device. Furthermore, the substrate is coupled to the device via the pads. Microdevices may have several layers, such as p-layers, n-layers, barrier layers, buffer layers, ohmic layers, and active layers. The active layer may be a multiple quantum well (MQW).

[0021] Figure 1A illustrates a method for forming a microdevice with an optical structure on a donor substrate. The method includes holding microdevices 102a, 102b, and 102c (hereinafter referred to as 102a, 102b, and 102c) on a substrate 100 using a layer 104. Layer 104 may be a polymer, such as BCB, polyamide, SU8, or other types. This layer may also cover devices 102a, 102b, and 102c. Multiple protective layers 106 may be present. A portion of the protective layer 106 may cover the device. A stack of reflective layers, dielectric layers, and stop layers may be present. Devices 102a, 102b, and 102c may be transferred from another substrate to the donor / temporary substrate 100. Alternatively, devices 102a, 102b, and 102c may be formed on the substrate 100. A passivation layer, anchoring layer, or optical layer 110 may be formed on at least a portion of the device. Layer 110 may also extend and be patterned outside of devices 102a, 102b, and 102c. Layer 110 may form anchors or bridging elements to hold the devices in place and release them during transfer to the system substrate. Optical layers 108a, 108b, and 108c may be formed and aligned with devices 102a, 102b, and 102c. Each device 102a, 102b, and 102c may have more than one type of optical layer to customize the functionality of each device. In one case, optical layers 108a, 108b, and 108c may be color conversion layers. In another related case, optical layers 108a, 108b, and 108c may be lens structures. Alternatively, optical layers 108a, 108b, and 108c may also be a combination of lenses and color conversion layers or color filter layers. In one case, different optical layers are formed by patterning. For example, layer 108a is formed and patterned on top of device 102a. Then, another layer 108b is formed and patterned on top of 102b. This process can continue until all desired layers are formed. In another case, these layers can be printed or stamped. Other methods can also be used to form the optical layers. After forming the optical layers, a passivation layer 112 can be formed on top of the device. The passivation layer 112 may also include an anchoring layer. In the case of an anchoring layer, the anchoring layer is patterned on the outside of devices 102a, 102b, and 102c. In a related case, a release layer 114 is formed. Here, the release layer is patterned and aligned with the optical layers 108a, 108b, and 108c and the device layers 102a, 102b, and 102c.

[0022] In another related scenario, as shown in Figure 1B, devices 102a, 102b, and 102c are etched back to create a housing structure 102-1 for at least a portion of optical layers 108a, 108b, and 108c (hereinafter referred to as 108a, 108b, and 108c). A portion of optical layers 108a, 108b, and 108c is formed within the housing structure 102-1. Other layers as described above may be formed after optical layers 108a, 108b, and 108c in the housing structure 102-1. In one method, devices 102a, 102b, and 102c are formed (or transferred) to a substrate. The sidewalls of the devices are covered with different housing layers 102-1. Layers 102-1 may include dielectric and / or reflective layers. Following this process, the top or bottom surface of the devices is etched back to expose the sidewalls, thereby forming a housing cavity on the top or bottom surface. An optical layer is formed on the top or bottom surface, and at least a portion of the optical layer is within the housing cavity formed by the housing layer 102-1. Other layers may exist before or after the optical layer. In another related method, the etch-back process may include patterning the device material and leaving some of the device material on the sidewalls, and only etching back the internal portion of the top or bottom surface. Thus, the remaining layers form the housing layer 102-1 or are portions of the housing layer 102-1. The etch-back process may be performed by a wet etching or dry etching process. The housing layer may be formed by various deposition processes such as PECVD, ALD, spin coating, printing, or other related methods. The processes described in Figure 1B can be used to form and manufacture other related devices and methods described herein.

[0023] Release layer 114 may be patterned, as shown in FIG1C. Here, the device can be transferred from substrate 100 to system (recipient) substrate. In this case, protective layer 106 may include a release layer that can be removed from layer 104 to the separated portions of microdevices 102a, 102b, 102c. The transfer can be performed directly by bringing the donor substrate 100 to the recipient substrate and aligning it. Here, the device can be bonded to the recipient substrate and left on the recipient substrate by mechanical or laser release. In another related case, the microdevice can be picked up from donor substrate 100 and transferred to recipient substrate.

[0024] In another related case, as shown in FIG1D, after forming layers on top of optical structures 108a, 108b, and 108c, a bonding layer 204 is used to bond substrate 200 to the top surface. Bonding layer 204 can be a polymer or other type of adhesive material. Here, substrate 100 is a removable temporary substrate (FIG. 1E). Furthermore, bonding layer 104 can be removed, thereby exposing the original bottom surfaces of devices 102a, 102b, and 102c. Here, surfaces are exchanged according to definition. Some of the protective layers can be removed or patterned. In one related case, a portion of protective layer 106 covers some surfaces of the device not covered by the optical structures. The remaining active layer 106 can be reflective. Layers 110 or 112 can be patterned to form anchors. In another case, one of layers 110, 112, or 204 can also be a temporary adhesive for releasing the device under different conditions. Here, release layer 114 can be removed. The substrate can be selectively bonded to the acceptor substrate, and the device is released to the acceptor substrate. In another case, a laser is used to release layer 112 and transfer the device to the acceptor substrate.

[0025] Figures 2A and 2B illustrate another related embodiment. Here, there is no layer between devices 102a, 102b, and 102c. Layer 112 also covers the sidewalls of the devices. Here, layer 106 or 104 may be a temporary adhesive that releases the devices under certain conditions (e.g., temperature, light, etc.). In another related case, layer 106 may be a release layer. It is patterned so that layer 112 is attached to the device wall. Figure 2B shows an exemplary pattern. Layer 106 is removed in pattern 302. The deposited layer 112 may also be patterned to cover only the pattern 302 on the sidewalls. After the release layer is removed, devices 102a, 102b, and 102c are connected to layer 104 via layer 112 connected by pattern 302. Here, after the microdevice is bonded to the acceptor substrate, layer 112 breaks, leaving the device in the acceptor substrate.

[0026] In another related embodiment shown in Figure 2C, a release layer 402 is formed beneath devices 102a, 102b, and 102c. Here, the release layer can be removed to prepare the device for transfer.

[0027] In another related embodiment shown in Figure 2D, an anchoring layer 404 is also formed below the device, and a release layer 402 is formed between the bonding layer 104 and the anchoring layer 404.

[0028] Figure 3A illustrates an exemplary embodiment of a microdevice with an optical layer integrated within the device. Device 102 is covered by a protective layer having sublayers 106-1, 106-2, and 106-3. The protective layer may include several sublayers, such as a dielectric layer (or high-bandwidth material) 106-1 surrounding device 102. It may be an optical layer reflecting 106-2 and another passivation layer 106-3. A portion of the protective layer may extend above the height of device 102, thereby forming a housing for holding the optical layer 108. An optical enhancement layer 110 may be present between the optical layer 108 and device 102. An encapsulation / passivation layer 112 may be used to cover at least a portion of the optical layer 112 or device 102 or other layers. Passivation layer 112 may include several sublayers, such as an anchoring layer, an optical enhancement layer, and other layers. The device may have solder pads on the top or bottom side. To form pad layers at the protective layers (106-1, 106-2, 106-3), these layers are patterned or formed around the pads to provide access to the microdevice 102. To form pads on the side of the optical layer 108, a passivation layer 112, an optical layer 108, and an optical enhancement layer 110 are patterned or formed around the pads.

[0029] Figure 3B illustrates an example of integrating the device of Figure 3A into a receiver substrate 500. The substrate may have pixel circuitry, metal traces, and other circuitry layers. It has a landing area 502. The landing area may have solder pads that connect to the pads of device 102. In this example, the surface of the device covered by a protective layer with sublayers (106-1, 106-2, 106-3) is connected to the substrate 500. If the solder pads are on this surface, they can be directly bonded to the solder pads in the landing area 502 of the substrate. The landing area may also have other layers to hold the device, such as an adhesive layer. If the solder pads of the device are on another surface, other layers (such as planarization, metallization, and vias) can be used to connect the device to the substrate. In another case, the substrate circuitry can be fabricated after the device is integrated into the substrate 500. Here, light input or output can pass through an optical layer. For example, in the case of a microLED, light generated by device 102 passes through optical layer 108. The optical layer may be for color conversion to convert the light from device 102 into different wavelengths, or it may be a lens structure to confine light or perform other types of optical functions. In this case, layer 106-2 may reflect light via optical layer 108. In another related case, light may pass through the substrate (emitted from the bottom). Here, there is no reflective layer in the protective layer, and the passivation layer 112 has a reflective layer.

[0030] Figure 3C illustrates an example of integrating the device of Figure 3A into a receiver substrate 500. The substrate may have pixel circuitry, metal traces, and other circuitry layers. It has a landing area 502. The landing area may have solder pads that connect to the pads of device 102. In this example, the surface of the device covered by optical layer 108 and passivation layer 112 is connected to the substrate 500. If the solder pads are on this surface, they can be directly bonded to the solder pads in the landing area 502 of the substrate. The landing area may also have other layers to hold the device, such as an adhesive layer. If the solder pads of the device are on another surface, other layers (such as planarization, metallization, and vias) can be used to connect the device to the substrate. In another case, the substrate circuitry can be fabricated after the device is integrated into the substrate 500. Here, light input or output can pass through optical layer 108 and substrate 500 (bottom emission). For example, in the case of microLEDs, light generated by device 102 passes through optical layer 108. The optical layer may be for color conversion to convert the light from device 102 into different wavelengths, or it may be a lens structure to confine light or perform other types of optical functions. In this case, layer 106-2 may reflect light via optical layer 108. In another related case, light may pass through the protective layer (emitted from the top). Here, there is no reflective layer in the protective layer, and passivation layer 112 may have a reflective layer.

[0031] While specific embodiments and applications of the invention have been described and illustrated, it should be understood that the invention is not limited to the precise constructions and compositions disclosed herein, and various modifications, variations and modifications will be apparent from the foregoing description without departing from the spirit and scope of the invention as defined in the appended claims.

[0032] 100:Substrate 102-a: Microdevice 102-b: Microdevice 102-c: Microdevice 102-1: Shell Structure 104: Floor 106: Protective layer 106-1: Protective layer 106-2: Protective layer 106-3: Protective layer 108: Optical layer 108-a: Optical layer / optical structure 108-b: Optical layer / optical structure 108-c: Optical layer / optical structure 110: Optical enhancement layer 112: Passivation layer 114: Release Layer 200:Substrate 204: Bonding layer 302: Pattern 402: Release layer 404: Anchoring layer 500: Receptor base plate 502: Landing Area

Claims

1. A method for forming a microdevice having an optical structure on a substrate, the method comprising: holding the microdevice on a top of the substrate, wherein the microdevice has a top side, a bottom side, and sidewalls different from the bottom side and the top side, and the top side facing away from the substrate; forming an optical layer on the top side of the microdevice; forming a passivation layer on top of the optical layer; and transferring the microdevice and the optical layer into a system substrate, wherein a protective layer is deposited on the sidewalls and at least a portion of the bottom side of the microdevice.

2. The method of claim 1, wherein the first layer covers the interface between the microdevice and the protective layer.

3. The method of claim 1, wherein the second layer covers a portion of the interface between the optical layer and the microdevice.

4. The method of claim 1, wherein the substrate is a donor substrate or a temporary substrate.

5. The method of claim 2, wherein the first layer is a polymer.

6. The method of claim 3, wherein the second layer is another passivation layer, anchoring layer, bridging layer or separate optical layer.

7. The method of claim 1, wherein the optical layer includes a color conversion layer.

8. The method of claim 1, wherein the optical layer comprises a color filter layer.

9. The method of claim 1, wherein the optical layer comprises a lens structure.

10. The method of claim 1, wherein the optical layer is a combination of a color conversion layer and a lens structure.

11. The method of claim 1, wherein the optical layer comprises different optical layers formed by patterning.

12. The method of claim 1, wherein the passivation layer also includes an anchoring layer.

13. The method of claim 12, wherein the anchoring layer is patterned on the exterior of the microdevice.

14. A method of forming a microdevice having an optical structure on a substrate, the method comprising: holding the microdevice on a top of the substrate, wherein the microdevice has a top side, a bottom side, and sidewalls different from the bottom side and the top side, and the top side facing away from the substrate; forming an optical layer on the top side of the microdevice; forming a passivation layer on top of the optical layer; and transferring the microdevice and the optical layer into a system substrate, wherein a release layer is formed and patterned and aligned with the optical layer and the microdevice.

15. The method of claim 14, wherein the release layer is further patterned to fit the optical layer.

16. The method of claim 1, wherein the microdevice is etched back to create a housing structure for at least a portion of the optical layer, wherein the portion of the optical layer is formed within the housing structure.

17. The method of claim 15, wherein an additional layer is formed on top of the optical layer, and a bonding layer is used to bond the second substrate to the top surface.

18. The method of claim 17, wherein the bonding layer is an adhesive or a polymer.

19. The method of claim 17, wherein the substrate is a temporary substrate that is removed together with a first layer holding the microdevice on the substrate, thereby exposing the original bottom surface of the microdevice.

20. The method of claim 19, wherein the protective layer deposited on the sidewalls and at least a portion of the bottom side of the microdevice is removed or patterned.

21. The method of claim 19, wherein a portion of the protective layer covers a portion of the microdevice, and the remainder is reflective.

22. The method of claim 19, wherein the second layer covers a portion of the interface between the optical layer and the microdevice, and the second layer or the passivation layer is patterned to form an anchor, a bridging element, or a diaphragm.

23. The method of claim 19, wherein the second layer covers a portion of the interface between the optical layer and the microdevice, and the second layer, the passivation layer, or the bonding layer is a temporary adhesive that releases the microdevice under different conditions, wherein the release layer is further removed.

24. A method of forming a microdevice having an optical structure on a substrate, the method comprising: holding the microdevice on a first bonding layer on top of the substrate; covering the microdevice with a first layer; covering the microdevice with a protective layer; forming an optical layer aligned with the microdevice on top of the first bonding layer; and forming a passivation layer on top of the optical layer such that the passivation layer also covers the sidewalls of the microdevice.

25. The method of claim 24, wherein the protective layer or the first bonding layer is a temporary adhesive that releases the microdevice under certain conditions.

26. The method of claim 24, wherein a removable release layer is formed beneath the microdevice to allow for microdevice transfer.

27. The method of claim 24, wherein an anchoring layer is also formed beneath the microdevice, and a release layer is formed between the first bonding layer and the anchoring layer.

28. A method for integrating a microdevice with an optical structure, the method comprising: covering the microdevice with a protective layer; extending a portion of the protective layer to form a housing; and securing the optical layer within the housing.

29. The method of claim 28, further comprising having an optical enhancement layer between the optical layer and the microdevice.

30. The method of claim 28, further comprising covering at least a portion of the optical layer or the microdevice with a first passivation layer.

31. The method of claim 28, wherein the protective layer has a sublayer comprising a dielectric layer, a reflective layer and a second passivation layer.

32. The method of claim 30, wherein the first passivation layer has a sublayer comprising an anchor and another optical enhancement layer.

33. The method of claim 30, wherein the microdevice has pads on the top or bottom side.

34. The method of claim 33, wherein a pad layer is formed at the protective layer, wherein a sublayer of the protective layer is patterned or formed around the pad to provide access to the microdevice.

35. The method of claim 33, wherein a pad is formed on the optical layer side, wherein the first passivation layer, the optical layer, and the optical enhancement layer between the optical layer and the microdevice are patterned or formed around the pad.

36. The method of claim 33, wherein the microdevice is integrated into a receiver substrate having a landing area.

37. The method of claim 36, wherein the landing area has a pad connected to the pad of the microdevice.

38. The method of claim 37, wherein the protective layer is attached to the receptor substrate.

39. The method of claim 37, wherein the landing area has an adhesive layer.

40. The method of claim 36, wherein the pads of the microdevice are on another surface, and planarization, metallization, and vias are used to connect the microdevice to the receiver substrate.

41. The method of claim 36, wherein the receptor substrate has a circuit system including pixel circuitry, metal traces, and additional circuitry layers.

42. The method of claim 41, wherein the circuitry of the receptor substrate is fabricated after the microdevice is integrated into the receptor substrate and light input or output passes through the optical layer.

43. The method of claim 42, wherein the reflective layer of the protective layer reflects the light passing through the optical layer.

44. The method of claim 41, wherein light passes through the receptor substrate, and there is no reflective layer in the protective layer, and the first passivation layer has a reflective layer.

45. The method of claim 37, wherein the surface of the microdevice covered by the optical layer and the first passivation layer is connected to the receptor substrate.

46. ​​The method of claim 45, wherein the landing area has an adhesive layer.

47. The method of claim 45, wherein the pads of the microdevice are on another surface, and planarization, metallization, and vias are used to connect the microdevice to the receiver substrate.

48. The method of claim 45, wherein the receptor substrate has a circuit system including pixel circuitry, metal traces, and additional circuitry layers.

49. The method of claim 48, wherein the circuitry of the receptor substrate is fabricated after the microdevice is integrated into the receptor substrate and light input or output passes through the optical layer.

50. The method of claim 49, wherein the reflective layer of the protective layer reflects the light passing through the optical layer.

51. The method of claim 48, wherein light passes through the receptor substrate and there is no reflective layer in the protective layer, and the first passivation layer has a reflective layer.

52. A method of forming a microdevice having an optical structure on a substrate, the method comprising: holding the microdevice on a top of the substrate, wherein the microdevice has a top side, a bottom side, and sidewalls different from the bottom side and the top side, and the top side facing away from the substrate; forming an optical layer on the top side of the microdevice; forming a passivation layer on top of the optical layer; and transferring the microdevice and the optical layer into a system substrate, wherein the microdevice is formed on the substrate; and wherein the sidewalls of the microdevice are covered with different shell layers, the shell layers comprising a dielectric and / or a reflective layer.

53. The method of claim 52, wherein the top or bottom surface of the microdevice is etched back to expose the sidewalls, thereby forming a housing cavity on the top or bottom surface.

54. The method of claim 53, wherein an optical layer is formed on the top or bottom surface, and at least a portion of the optical layer is inside the housing cavity formed by the housing layer.

55. The method of claim 54, wherein there are other layers before or after the optical layer.

56. The method of claim 53, wherein the etch-back process includes patterning and leaving some material of the microdevice on the sidewall, and etching back only the inner portion of the top or bottom surface.

57. The method of claim 53, wherein the etching process is performed by a wet etching or a dry etching process, and the outer shell layer is formed by different deposition processes.

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