WO2020018255A1

WO2020018255A1 - Stretchable electronics and hybrid integration method for fabricating the same

Info

Publication number: WO2020018255A1
Application number: PCT/US2019/039802
Authority: WO
Inventors: Ze YUAN; Jiahao KANG; Ximeng Guan; Peng Wei
Original assignee: Shenzhen Royole Technologies Co. Ltd.
Priority date: 2018-07-20
Filing date: 2019-06-28
Publication date: 2020-01-23
Also published as: WO2020018256A1

Abstract

This application discloses a stretchable electronic device and a hybrid integration method for fabricating the same. The stretchable electronic device includes a stretchable layer including a first surface. The stretchable electronic device also includes a plurality of electronic devices disposed at discrete locations on the first surface of the stretchable layer. The stretchable electronic device further includes a plurality of stretchable interconnects. Each stretchable interconnect electrically interconnects one electronic device to another electronic device respectively. The stretchable electronic device further includes a support layer including a first set of patterns providing supports to the plurality of the electronic devices. The plurality of electronic devices are disposed between the stretchable layer and the support layer.

Description

STRETCHABLE ELECTRONICS AND HYBRID

INTEGRATION METHOD FOR FABRICATING THE SAME

TECHNICAL FIELD

[0001] This application relates generally to flexible and stretchable electronic devices, and more specifically, to flexible and stretchable electronic devices and a hybrid integration method for manufacturing the same that starts from providing a rigid substrate, followed by forming a support layer on the rigid substrate for supporting at least the electronic devices, introducing a stretchable layer (also referred to as flexible layer, elastomer layer, elastomer encapsulation, elastomer substrate, stretchable substrate), and detaching the elastomer layer from the rigid substrate to form the flexible and stretchable electronic devices.

BACKGROUND

[0002] Stretchable and flexible electronics is a technology for building electronic circuits with stretchability (e.g., elasticity) and flexibility. Currently, stretchable and flexible electronics are of great interest for application in wearable devices, electronic newspapers, smart identity cards and many other consumer electronics. A conventional method of fabricating stretchable electronics includes pre-stretching a stretchable substrate and patterning conductive interconnects on the pre-stretched substrate. Then chiplets are transferred onto the pre-stretched substrate and bonded with the interconnects. However, after relaxing the substrate, the stretchable device is often buckled with wavy, checkerboard, and/or herringbone issues.

[0003] Another conventional method of fabricating stretchable electronics includes pre-stretching a stretchable substrate and transferring conductive interconnects onto the pre- stretched substrate. Chiplets are then transferred onto the pre-stretched substrate and bonded with the interconnects. However, after relaxing the substrate, certain parts of the

interconnects often extend out of the substrate plane and thus the stretchable electronics become non-coplanar.

[0004] Yet another method of fabricating stretchable electronics includes patterning co-planar interconnects on a stretchable substrate in a relaxed state, and then transferring and bonding the chiplets with the interconnects. However, fabricating stretchable electronics directly on stretchable substrates often result in problems in low production yield, reduced cost-effectiveness, limited production scaling, and poor device integratability. The stretchable substrates may not be compatible with current semiconductor and display panel technologies due to, for example, form factor and thermal budget. Additionally, the complexity of the circuits may be limited by the form factor and the mechanical property of the stretchable substrates.

[0005] Therefore, it would be beneficial to have stretchable and flexible electronics with uncompromised robustness, uncompromised resolution, improved mechanical integrity, and improved production yield and cost-effectiveness, and methods for fabricating the same.

SUMMARY

[0006] Hybrid integrated circuits are fabricated by interconnecting a number of individual chips that are prefabricated. Hybrid integration can be used for fabricating stretchable electronics. The method includes encapsulating prefabricated electronic devices (e.g., chiplets) by stretchable layers. In some embodiments, the stretchable layers include rubbers (natural or synthetic) or thermoplastic elastomers. Based on the design, chiplets included in the stretchable electronics can be used for computing, data storage, sensing, communicating and informative display. In some embodiments, the chiplets are

interconnected with conductive interconnects designed with certain stretchability.

[0007] In accordance with one aspect of this application, a stretchable electronic device includes a stretchable layer including a first surface. The stretchable electronic device further includes a plurality of electronic devices disposed at discrete locations on the first surface of the stretchable layer. The stretchable electronic device also includes a plurality of stretchable interconnects. Each stretchable interconnect electrically interconnects one electronic device to another electronic device respectively. The stretchable electronic device further includes a support layer including a first set of patterns providing supports to the plurality of the electronic devices. As discussed elsewhere herein, the support layer may be patterned at any stage during the process. In one example, the support layer is patterned at the beginning of the process, e.g., prior to forming the stretchable interconnects. In another example, the support layer is patterned at a later stage during the process, e.g., after forming the stretchable interconnects. The plurality of electronic devices and the plurality of stretchable interconnects are disposed between the stretchable layer and the support layer.

[0008] In accordance with another aspect of this application, a method is

implemented to form a stretchable electronic device. The method includes providing a rigid substrate including a first surface, and forming a support layer on the first surface of the rigid substrate. The support layer includes a first set of patterns and a second set of patterns that interconnect with the first set of patterns respectively. A plurality of stretchable interconnects are supported by the second set of patterns of the support layer respectively. The method further includes attaching a plurality of electronic devices to the first set of patterns of the support layer respectively. Attaching the plurality of electronic devices to the first set of patterns further includes attaching a first side of a respective electronic device to a first surface of a corresponding pattern, and electrically interconnecting the plurality of electronic devices via the plurality of stretchable interconnects respectively. The method further includes depositing a stretchable layer on top of the plurality of the electronic devices, and removing the rigid substrate to obtain the stretchable device including the stretchable layer, the support layer, and the plurality of electronic devices and the plurality of stretchable interconnects disposed between the stretchable layer and the support layer.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] For a better understanding of the various described implementations, reference should be made to the Description of Implementations below, in conjunction with the following drawings in which like reference numerals refer to corresponding parts throughout the figures.

[0010] Figures 1 A-1D illustrate an example process for fabricating a stretchable electronic device in accordance with some implementations.

[0011] Figure 2 is a flowchart of an example method of fabricating a stretchable electronic device in accordance with some implementations.

[0012] Figures 3 A-3B illustrate an embodiment of forming a support layer for a stretchable electronic device in accordance with some implementations.

[0013] Figures 4A-4B illustrate an embodiment of forming a support layer for a stretchable electronic device in accordance with some implementations.

[0014] Figures 5A-5B illustrate an embodiment of forming a support layer for a stretchable electronic device in accordance with some implementations.

[0015] Figures 6A-6F illustrate an example process for fabricating a stretchable electronic device including a support layer that is formed as discussed with references to Figures 3 A-3B, 4A-4B, or 5A-5B, in accordance with some implementations. [0016] Figures 7A-7B illustrate examples of stretchable display devices in accordance with some implementations.

[0017] Like reference numerals refer to corresponding parts throughout the several views of the drawings.

DESCRIPTION OF IMPLEMENTATIONS

[0018] Instead of starting from a stretchable substrate as used in the conventional methods, the process of the present disclosure starts from a rigid substrate. A support layer (e.g., polyimide (PI), polyethylene naphthalate (PEN), polyethylene terephthalate (PET), polyurethane (PET), polydimethylsiloxane (PDMS), polystyrene (PS), polyethersulfone (PES), polyethylene (PE), or polyvinyl chloride (PVC)), is patterned and used to support the chiplets and optionally, the interconnects, from the bottom. As discussed elsewhere herein, the support layer maybe patterned at any stage during the process. Coplanar interconnects and chiplets are integrated on top of the support layer. An elastomer material is then formed (e.g., laminated onto the interconnects and chiplets structure through thermal or other suitable method, adhered to the interconnects and chiplets structure and film in the morphology of the layers below, coated on top of the interconnects and chiplets structure, etc.), and the whole stack (including support layer, the interconnects and chiplets, and the elastomer layer) is delaminated from the rigid substrate to obtain the stretchable electronic device.

[0019] The stretchable device and the method for fabricating the same provide numerous benefits including improved integration density, process compatibility, production yield, uncompromised resolution and robustness, and improved cost-effectiveness. The process disclosed herein starts from a rigid substrate, and the stretchable layer (also referred to as flexible layer, elastomer layer, elastomer encapsulation, elastomer substrate, stretchable substrate, elastomer material) is introduced at the final stage. Hence, the process can be adopted by the current semiconductor industry and display panel industry. Moreover, the support layer (e.g., the PI layer) provides robust mechanical support for the interconnects and the chiplets to improve the mechanical flexibility and stretchability of the stretchable electronic devices. In addition, the rigid substrate and the PI support structure used in the process discussed in the present disclosure can enable scaled and highly-condensed features and functionalities integrated into the stretchable electronic devices.

[0020] Figures 1 A-1D illustrate an example process for fabricating a stretchable electronic device 150 (e.g., Figure 1D) in accordance with some implementations. Figure 2 is a flowchart of an example method 200 of fabricating the stretchable electronic device 150 in accordance with some implementations. In some embodiments, the stretchable electronic device is also referred to as a flexible electronic device, a bendable electronic device, or a wearable electronic device.

[0021] As shown in Figure 1 A, a rigid substrate 102 is provided (e.g., step 202,

Figure 2). In some embodiments, the rigid substrate 102 includes one or more materials selected from glass, silicon, silicon dioxide, aluminum oxide, sapphire, germanium, III-V semiconductor material such as gallium arsenide (GaAs), indium phosphide (InP), gallium phosphide (GaP), gallium nitride (GaN), a II- VI semiconductor material, an alloy of silicon and germanium. In some embodiments, a delamination layer is further formed on the rigid substrate 102 (e.g., before forming the support layer 110). In some embodiments, the delamination layer is a removable layer that can later be detached from the rigid substrate 102. For example, the delamination layer is a sacrificial layer that can be etched away using wet etching, laser ablation, plasma etching, or a combination thereof.

[0022] In some embodiments as shown in Figure 1 A, a support layer 110 is formed

(e.g., step 204, Figure 2) on the rigid substrate 102. In some embodiments, the support layer 110 is formed of polyimide (PI). In some embodiments, the support layer 110 is made of other suitable polymer material, such as polyethylene naphthalate (PEN), polyethylene terephthalate (PET), polyurethane (PET), polydimethylsiloxane (PDMS), polystyrene (PS), polyethersulfone (PES), polyethylene (PE), or polyvinyl chloride (PVC). In some embodiments, the support layer 110 includes a first set of patterns 112 and a second set of patterns 114 that interconnect with the first set of patterns 112 respectively. In some embodiments, the first set of patterns 112 and the second patterns 114 are formed by lithography, printing, stamping, self-assembly, or any other suitable method.

[0023] In some embodiments as shown in Figure 1B, a plurality of stretchable interconnects 124 are formed on and supported by (e.g., step 204, Figure 2) the second set of patterns 114 respectively. For example, the plurality of stretchable interconnects 124 are deposited on the second set of patterns respectively. In some embodiments, the ends of the stretchable interconnects 124 are attached to the first set of patterns 112 to form contact with the respective electronic devices 122 so as to connect the electronic devices 122 with each other.

[0024] In some embodiments, a plurality of electronic devices 122 are transferred and attached to (e.g., step 206, Figure 2) the first set of patterns 112 of the support layer 110 respectively. In some embodiments, a first side of a respective electronic device 122 is attached (e.g., step 208, Figure 2) to a first surface of a corresponding support pattern 112 of the first set of patterns. In some embodiments, the plurality of electronic devices 122 are electrically interconnected (e.g., step 210, Figure 2) via the plurality of stretchable interconnects 124 respectively. For example, a respective electronic device is connected to one or more stretchable interconnects using a suitable method, including but not limited to wire bonding, or another suitable solder-based bonding process). In some embodiments, one or more electronic devices 122 are attached to the first set of patterns 112 respectively, and then one or more stretchable interconnects 124 are attached and form contacts on a second side of the respective electronic devices 122, opposite to the first side that is attached to the support pattern 112. In some embodiments as shown in Figure 1B, the stretchable interconnects 124 and the electronic devices 122 are integrated on top of respective support patterns of the support layer 110. In some embodiments, the lateral shape and dimension of the plurality of stretchable interconnects 124 are a subset of the second set of patterns 114. That is, the stretchable interconnects only partially occupy the support patterns. In some embodiments, the plurality of stretchable interconnects 124 and the second set of patterns 114 have identical lateral shape and dimension.

[0025] In some embodiments as shown in Figure 1C, a stretchable layer 132 is deposited (e.g., 212, Figure 2) on top of the plurality of the electronic devices 122 and the plurality of stretchable interconnects 124. In some embodiments, the stretchable layer 132 is deposited on a second side of the electronic device 122 opposite to the first side that is attached to the support pattern 112. That is, a respective electronic device 122 is sandwiched between the support layer 110 (e.g., including the support pattern 112) and the stretchable layer 132 as shown in Figure 1C. In some embodiments, the stretchable layer 132 are formed by depositing an elastomer polymer, such as natural rubber, synthetic rubber or thermoplastic elastomer (TPE), on top of the electronic devices 122 and the stretchable interconnects 124.

[0026] In some embodiments as shown in Figures 1C-1D, after forming the stretchable layer 132, the rigid substrate 102 is removed (e.g., step 214, Figure 2) from the stretchable layer 132 to obtain the stretchable device 150. In some embodiments, the rigid substrate 102 is detached from the stretchable layer 132 via laser ablation. In some embodiments, the rigid substrate 102 is mechanically peeled off from the stretchable layer 132. In some embodiments, the rigid substrate 102 is detached from the stretchable layer 132 by dissolving the sacrificial layer or ablating the sacrificial layer by laser, where the sacrificial layer was deposited on the rigid substrate 102 prior to forming the support layer 110.

[0027] In some embodiments as shown in Figure 1D, the stretchable device 150 includes the stretchable layer 132 having a first surface. In some embodiments, the plurality of electronic devices 122 are disposed at discrete locations on the first surface of the stretchable device 150. In some embodiments, a respective stretchable interconnect 124 electrically interconnects one electronic device to another electronic device. In some embodiments, the first set of patterns 112 of the support layer 110 provides support to the plurality of the electronic devices 122 respectively. In some embodiments, the second set of patterns 114 of the support layer 110 provides support to the plurality of stretchable interconnects 124 respectively. In some embodiments, the electronic devices 122 and the stretchable interconnects 124 are disposed between the stretchable layer 132 and the support layer 110 including the support patterns 112 and 114. Although not shown, in some embodiments, the stretchable device 150 includes only the first set of patterns without having the second set of patterns.

[0028] In some embodiments, the stretchable layer 132 comprises an elastomer material, such as a transparent elastomer (e.g., being absolute transparent). In some embodiments, the stretchable layer 132 comprises one or more natural rubbers. In some embodiments, the stretchable layer 132 comprises one or more synthetic rubbers. In some embodiments, the stretchable layer 132 comprises one or more thermoplastic elastomers (TPE). In some embodiments, the stretchable layer 132 has a thickness in a range from 10 pm to 5 mm.

[0029] In some embodiments, the plurality of stretchable interconnects 124 and the plurality of electronic devices 122 are coplanarly disposed on the first surface of the stretchable layer 132. In some embodiments, at least a portion of a respective stretchable interconnect overlaps with (e.g., attached to) a respective electronic device to connect this electronic device with another electronic device. In some embodiments, the overlapped stack between a stretchable interconnect and a corresponding electronic device can include either the stretchable interconnect disposed on top of the electronic device, or the electronic device on top of the stretchable interconnect.

[0030] In some embodiments, the first set of patterns 112 and the second set of patterns 114 in the support layer 110 are formed in a single step during a lithography process. Alternatively, the first and second set of patterns may be formed in separate steps. In some embodiments, the first and second set of patterns are formed before the electronic devices 122 and the stretchable interconnects 124 are attached to the support layer 110. In some embodiments, the first and second set of patterns are formed after the electronic devices 122 and the stretchable interconnects 124 are attached to the support layer 110. In some embodiments, the first and second set of patterns are formed after the stretchable

interconnects 124 are attached to the support layer 110 and before the electronic devices 122 are attached to the support layer 110. In some embodiments, the first and second set of patterns are formed after the electronic devices 122 are attached to the support layer 110 and before the stretchable interconnects 124 are attached to the support layer 110. In some embodiments, the support layer 110 includes polyimide (PI), polyethylene naphthalate (PEN), polyethylene terephthalate (PET), polyurethane (PET), polydimethylsiloxane (PDMS), polystyrene (PS), polyethersulfone (PES), polyethylene (PE), or polyvinyl chloride (PVC).

In some embodiments, the support layer 110 has a thickness in a range from 1 pm to 10 pm.

In some embodiments, the support layer 110 includes only the first set of patterns 112 configured to support the electronic devices 122 respectively. The stretchable interconnects 124 are disposed on the stretchable layer 132 without any support. The reduced area of the support layer may improve stretchability and flexibility of the stretchable device 150.

[0031] In some embodiments, the plurality of stretchable interconnects 124 are formed from one or more materials selected from metal, carbon ink, silver ink, and conductive polymers.

[0032] In some embodiments, a respective electronic device 122 (e.g., a chiplet, or a subcircuit) is pre-fabricated prior to attaching to the corresponding pattern. In some embodiments, an electronic device 122 is a die with a predetermined functional circuit. In some embodiments, the plurality of electronic devices 122 include a plurality of pixel driving circuits formed from thin film transistors (TFT) respectively. In some embodiments, a respective pixel driving circuit is configured to control a display pixel of the stretchable device 150. In some embodiments, a respective electronic device 122 of the plurality of electronic devices is a sensor selected from a group consisting of a wearable sensor, a gyro accelerator, a pressure sensor, an optical sensor, a temperature sensor, a chemical sensor, a gas sensor, a biosensor, and a diagnostic sensor. In some embodiments, a respective electronic device 122 of the plurality of electronic devices includes a silicon semiconductor. In some embodiments, a respective electronic device 122 of the plurality of electronic devices includes a III-V semiconductor. In some embodiments, a respective electronic device 122 of the plurality of electronic devices includes a telecommunication circuit. In some

embodiments, a respective electronic device of the plurality of electronic devices is a surface- mount device (SMD). In some embodiments, a respective electronic device of the plurality of electronic devices is an energy storage device such as a battery or a supercapacitor. In some embodiments, the stretchable device 150 is a liquid crystal display device, an active matrix organic light-emitting diode (OLED) device, an organic light-emitting electrochemical cell, a mini light-emitting diode (LED), or a micro LED.

[0033] In some embodiments, a respective electronic device 122 has a thickness in a range from 1 pm to 1 mm. For example, an electronic device 122 has a thickness of 3-5 pm. In another example, an electronic device 122 including a surface-mount device (SMD) has a thickness of no thicker than 1 mm. In some embodiments, a respective electronic device 122 has a size in a range from 10 pm to 10 mm along a dimension that is parallel to the first surface of the stretchable layer 132. For example, an electronic device 122 has a square shape with a dimension of several tens of micrometers. In another example, an electronic device 122 including a surface-mount device (SMD) has a dimension of no bigger than 10 mm. It is to be understood that these dimensions are exemplary and are not intended to be limiting. In some embodiments, a respective subcircuit 122 including packaging may have any other dimensions that are suitable and/or necessary for building the stretchable device.

[0034] Figures 3 A-3B illustrate an embodiment of forming a support layer 310 for a stretchable electronic device (e.g., stretchable electronic device 650, Figure 6F) in accordance with some implementations. In some embodiments, forming the support layer 310 includes depositing a first layer 304 on the rigid substrate 302. In some embodiments, the first layer 304 is formed of polyimide (PI), polyethylene naphthalate (PEN), polyethylene terephthalate (PET), polyurethane (PU), polydimethylsiloxane (PDMS), polystyrene (PS), polyethersulfone (PES), polyethylene (PE), or polyvinyl chloride (PVC).

[0035] In some embodiments, forming the support layer 310 further includes patterning the first layer 304 to form the first set of patterns 312 and the second set of patterns 314 of the support layer 310 as shown in Figure 3B. In some embodiments, the first set of patterns 312 and the second set of patterns 314 are formed by patterning a PI layer 304 via photolithography. In some other embodiments, the first set of patterns 312 and the second set of patterns 314 are formed by a suitable etching process performed to a PI layer 304, such as wet etching, dry etching (e.g., plasma etching), or a combination thereof. [0036] In some embodiments, after forming the first set of patterns 312 and the second set of patterns 314, a plurality of stretchable interconnects (e.g., the stretchable interconnects 624, Figure 6 A) are formed on the second set of patterns (the second set of patterns 314 or 614 of Figure 6A) of the support layer respectively. In some embodiments, the rigid substrate 302, the support layer 310, the first set of patterns 312 and the second set of patterns 314 in the support layer 310 are substantially similar to the rigid substrate 102, the support layer 110, the first set of patterns 112 and the second set of patterns 114 in the support layer 110 as discussed with reference to Figure 1 A.

[0037] Figures 4A-4B illustrate an embodiment of forming a support layer 410 for a stretchable electronic device (e.g., stretchable electronic device 650, Figure 6F) in accordance with some implementations. In some embodiments, forming the support layer 410 includes depositing the first set of patterns 412 and the second set of patterns 414 in the support layer 410 on the first surface of the rigid substrate 402. For example, the first set of patterns 412 and the second set of patterns 414 are directly deposited on the rigid substrate 402 using a mask 404 by printing, stamping, slot die coating, or shadow mask lithography (e.g., stencil lithography). In some embodiments, the first set of patterns 412 and the second set of patterns 414 are directly formed on the rigid substrate using a self-assembly process.

[0038] In some embodiments, after forming the first set of patterns 412 and the second set of patterns 414, a plurality of stretchable interconnects (e.g., the stretchable interconnects 624, Figure 6 A) are formed on the second set of patterns (the second set of patterns 314 or 614 of Figure 6A) of the support layer respectively. In some embodiments, the rigid substrate 402, the support layer 410, the first set of patterns 412 and the second set of patterns 414 in the support layer 410 are substantially similar to the rigid substrate 102, the support layer 110, the first set of patterns 112 and the second set of patterns 114 in the support layer 110 as discussed with reference to Figure 1 A.

[0039] Figures 5A-5B illustrate an embodiment of forming a support layer 510 for a stretchable electronic device (e.g., stretchable electronic device 650, Figure 6F) in accordance with some implementations. In some embodiments, forming the support layer 510 includes depositing a first layer 504 that covers the first surface of the rigid substrate 502. In some embodiments, the first layer 504 is formed of polyimide (PI), polyethylene naphthalate (PEN), polyethylene terephthalate (PET), polyurethane (PET), polydimethylsiloxane (PDMS), polystyrene (PS), polyethersulfone (PES), polyethylene (PE), or polyvinyl chloride (PYC). In some embodiments, the first layer 504 (or the support layer 510) includes multiple layers, where the multiple layers are formed by different materials with different patterns.

[0040] In some embodiments, after depositing the first layer 504 on the rigid substrate

502, a plurality of stretchable interconnects 524 (e.g., which are substantially similar to the stretchable interconnects 624, Figure 6A) are formed on the first layer 504. In some embodiments, the stretchable interconnects 524 are fabricated using any suitable method, such as depositing a metal layer followed by patterning the metal layer to form the stretchable interconnects, depositing the stretchable interconnects through a mask, or printing conductive ink with predetermined patterns as discussed elsewhere herein. In some embodiments, the stretchable interconnects 524 include one or more materials selected from metal, carbon ink, silver ink, and conductive polymers.

[0041] In some embodiments, after forming the stretchable interconnects 524 on the first layer 504, the stretchable interconnects 524 are used as masks for patterning (e.g., by lithography or etching) the first layer 504 to form the second set of patterns (e.g., the second set of patterns 614, Figure 6A) in the following steps. In some embodiments, the first set of patterns (e.g., the first set of patterns 612, Figure 6A) are also formed by patterning the first layer 504 within the same process as forming the second set of patterns 614 using masks. In some embodiments, the first set of patterns 612 are formed using a different method and at a separate step from forming the second set of patterns 612. In some embodiments as discussed with reference to Figures 1 A-1D, the first set of patterns and the second set of patterns are used for supporting corresponding electronic devices and corresponding stretchable interconnects in the stretchable electronic device respectively.

[0042] There are multiple ways to form the support layer including the first set of patterns for supporting the electronic devices and the second set of patters for supporting the stretchable interconnects. In some embodiments, the sequence to form the first set of patterns in the support layer, to form the second set of patterns in the support layer, to attach the plurality of electronic devices to the first set of patterns respectively, and to attach the plurality of stretchable interconnects to the second set of patterns respectively can vary.

[0043] In some embodiments, forming the support layer comprises: depositing a first layer that covers the first surface of the rigid substrate; patterning the deposited first layer to form the support layer including the first set of patterns and the second set of patterns;

attaching the plurality of electronic devices to the first set of patterns; and forming the plurality of stretchable interconnects on the second set of patterns of the support layer respectively.

[0044] In some embodiments, forming the support layer comprises: depositing the support layer including the first set of patterns and the second set of patterns on the first surface of the rigid substrate; attaching the plurality of electronic devices to the first set of patterns, and forming the plurality of stretchable interconnects on the second set of patterns of the support layer respectively.

[0045] In some embodiments, forming the support layer comprises: depositing a first layer that covers the first surface of the rigid substrate; fabricating the plurality of stretchable interconnects on the first layer; and patterning the first layer to form the first set of patterns corresponding to the plurality of electronic devices and the second set of patterns

corresponding to the plurality of stretchable interconnects.

[0046] In some embodiments, forming the support layer comprises: depositing a first layer that covers the first surface of the rigid substrate; attaching a plurality of electronic devices to on the first layer; patterning the first layer to form the first set of patterns corresponding to the plurality of electronic devices and the second set of patterns

corresponding to the plurality of stretchable interconnects; and fabricating the plurality of stretchable interconnects on the second set of patterns.

[0047] In some embodiments, forming the support layer comprises: depositing a first layer that covers the first surface of the rigid substrate; attaching a plurality of electronic devices and fabricating the plurality of stretchable interconnects on the first layer; and patterning the first layer to form the first set of patterns corresponding to the plurality of electronic devices and the second set of patterns corresponding to the plurality of stretchable interconnects.

[0048] Figures 6A-6F illustrate an example process for fabricating a stretchable electronic device (e.g., stretchable electronic device 650, Figure 6F) including a support layer 610 (e.g., similar to the support layer 310 or 410, or the layer 504) that is formed on as discussed with references to Figures 3A-3B, 4A-4B, or 5A-5B respectively, in accordance with some implementations.

[0049] In some embodiments as shown in Figure 6A, after forming the first set of patterns 612 and the second set of patterns 614 of the support layer 610 (e.g., as discussed with reference to Figures 3 A-3B and 4A-4B), a plurality of stretchable interconnects 624 (e.g., substantially similar to stretchable interconnects 124, Figures 1 A-1D) are formed on the second set of patterns 614 of the support layer respectively. In some embodiments, the stretchable interconnects 624 are formed by depositing a metal layer followed by patterning the metal layer to form the stretchable interconnects 624 using a lithography or an etching process. In some embodiments, the stretchable interconnects 624 are formed by depositing the stretchable interconnects 624 through a mask on the second set of patterns 614. In some embodiments, the stretchable interconnects 624 are formed by printing conductive ink on the second set of patterns 614. In some embodiments, the stretchable interconnects 624 include one or more materials selected from metal, carbon ink, silver ink, and conductive polymers.

[0050] In some embodiments as shown in Figure 6B, a plurality of electronic devices

622 are transferred to be placed on the first set of patterns 612 respectively. In some embodiments, the electronic devices 622 are substantially similar to the electronic devices 122 as discussed with reference to Figures 1 A-1D. In some embodiments as shown in Figure 6C, the electronic devices 622 are electrically interconnected with each other via the stretchable interconnects 624 (e.g., via wire bonding) as discussed in step 210 of method 200 with reference to Figure 2. In some embodiments as shown in Figure 6D, a stretchable layer 632 (e.g., an elastomer layer) is deposited on the rigid substrate 602 to cover the electronic devices 622 and the stretchable interconnects 624 as discussed in step 212 of method 200 with reference to Figure 2. In some embodiments as shown in Figure 6E, the rigid substrate 602 is removed from the stretchable layer 632 by laser ablation, mechanical peeling, dissolving the sacrificial layer, or any other suitable method as discussed elsewhere herein (e.g., step 214 of method 200, Figure 2).

[0051] As shown in Figure 6F, the stretchable device 650 is obtained after detaching the rigid substrate 602 from the stretchable layer 632. In some embodiments, the stretchable device 650 is substantially similar to the stretchable device 150. For example, the rigid substrate 602, the support layer 610, the first set of patterns 612 and the second set of patterns 614 in the support layer 610 are substantially similar to the rigid substrate 102, the support layer 110, the first set of patterns 112 and the second set of patterns 114 in the support layer 110 respectively as discussed with reference to Figures 1 A-1D. In some embodiments, the plurality of electronic devices 622 and the plurality of stretchable interconnects 624 are substantially similar to the electronic devices 122 and the stretchable interconnects 124 respectively as discussed with reference to Figures 1 A-1D. Although not shown, in some embodiments, a second stretchable layer is attached to the stretchable layer 632 on the side from where the rigid substrate 602 was detached.

[0052] Figures 7A-7B illustrate an example of a stretchable and flexible display device 700 in accordance with some implementations. In some embodiments, the stretchable display device 700 includes a stretchable layer 732 that is formed of elastomer polymer. In some embodiments, the flexible display device 700 includes a plurality of electronic devices 722 (e.g., subcircuits, islands) embedded in the elastomer layer 732. The plurality of electronic devices 722 are interconnected using stretchable interconnects 724. In some embodiments as shown in the zoomed-in view in Figure 7B, a respective electronic device 722 corresponds to a display pixel (e.g., including red, green, and blue components) fabricated on an island. In some embodiments, the stretchable display device 700 further includes a PI support layer having respective support patterns 712 and 714 for supporting the display pixels 722 and the stretchable interconnects 724 respectively. In some embodiments, the stretchable display device 700 is fabricated using method 200 as discussed with reference to Figure 2.

[0053] It should be understood that the stretchable electronic devices described in this application are merely exemplary and are not intended to indicate that they are the only stretchable substrate devices that can be implemented in this application. One of ordinary skill in the art would recognize various ways to form a stretchable electronic device based on the devices and methods as described herein.

[0054] The foregoing description, for purpose of explanation, has been described with reference to specific implementations. However, the illustrative discussions above are not intended to be exhaustive or to limit the scope of the claims to the precise forms disclosed. Many modifications and variations are possible in view of the above teachings. The implementations were chosen in order to best explain the principles underlying the claims and their practical applications, to thereby enable others skilled in the art to best use the implementations with various modifications as are suited to the particular uses contemplated.

[0055] Reference has been made in detail to implementations, examples of which are illustrated in the accompanying drawings. In the detailed description, numerous specific details are set forth in order to provide a thorough understanding of the various described implementations. However, it will be apparent to one of ordinary skill in the art that the various described implementations may be practiced without these specific details. In other instances, well-known methods, procedures, components, mechanical structures, circuits, and networks have not been described in detail so as not to unnecessarily obscure aspects of the implementations.

[0056] It will also be understood that, although the terms first, second, etc. are, in some instances, used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first fastener structure can be termed a second fastener structure, and, similarly, a second fastener structure can be termed a first fastener structure, without departing from the scope of the various described implementations. The first fastener structure and the second fastener structure are both fastener structures, but they are not the same fastener structure.

[0057] The terminology used in the description of the various described

implementations herein is for the purpose of describing particular implementations only and is not intended to be limiting. As used in the description of the various described

implementations and the appended claims, the singular forms“a”,“an” and“the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will also be understood that the term“and/or” as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items. It will be further understood that the terms“includes,”“including,”“comprises,” and/or“comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, components, structures and/or groups, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, structures, and/or groups thereof.

[0058] As used herein, the term“if’ is, optionally, construed to mean“when” or

“upon” or“in response to determining” or“in response to detecting” or“in accordance with a determination that,” depending on the context. Similarly, the phrase“if it is determined” or “if [a stated condition or event] is detected” is, optionally, construed to mean“upon determining” or“in response to determining” or“upon detecting [the stated condition or event]” or“in response to detecting [the stated condition or event]” or“in accordance with a determination that [a stated condition or event] is detected,” depending on the context.

[0059] It is noted that the flexible substrate devices described herein are exemplary and are not intended to be limiting. For example, any dimensions, shapes, profiles, and/or materials described herein are exemplary and are not intended to be limiting. Drawings are not to scale. For brevity, features or characters described in association with some implementations may not necessarily be repeated or reiterated when describing other implementations. Even though it may not be explicitly described therein, a feature or characteristic described in association with some implementations may be used by other implementations.

Claims

What is claimed is:

1. A stretchable device, comprising:

a stretchable layer including a first surface;

a plurality of electronic devices disposed at discrete locations on the first surface of the stretchable layer;

a plurality of stretchable interconnects, each stretchable interconnect electrically interconnecting one electronic device to another electronic device respectively; and

a support layer including a first set of patterns providing support to the plurality of the electronic devices, wherein the plurality of electronic devices are disposed between the stretchable layer and the support layer.

2. The stretchable device of claim 1, wherein the stretchable layer comprises a transparent elastomer.

3. The stretchable device of claim 1, wherein the stretchable layer comprises natural rubber, synthetic rubber, or thermoplastic elastomer (TPE).

4. The stretchable device of claim 1, wherein the stretchable layer has a thickness in a range from 10 pm to 5 mm.

5. The stretchable device of claim 1, wherein the support layer includes one or more materials selected from a group consisting of polyimide (PI), polyethylene naphthalate (PEN), polyethylene terephthalate (PET), polyurethane (PET), polydimethylsiloxane (PDMS), polystyrene (PS), polyethersulfone (PES), polyethylene (PE), and polyvinyl chloride (PVC).

6. The stretchable device of claim 1, wherein the support layer further comprises a second set of patterns that are interconnected with the first set of patterns in the support layer, and wherein the plurality of stretchable interconnects are supported by the second set of patterns respectively in the support layer.

7. The stretchable device of claim 6, wherein the lateral shape and dimension of the plurality of stretchable interconnects are a subset of the second set of patterns

8. The stretchable device of claim 6, wherein the plurality of stretchable interconnects and the second set of patterns have identical lateral shape and dimension.

9. The stretchable device of claim 1, wherein the support layer has a thickness in a range from 1 pm to 10 pm.

10. The stretchable device of claim 1, wherein the plurality of electronic devices includes a plurality of pixel driving circuits formed from thin film transistors (TFT).

11. The stretchable device of claim 1, wherein a respective electronic device of the plurality of electronic devices includes a sensor selected from a group consisting of a wearable sensor, a gyro accelerator, a diagnostic sensor, a pressure sensor, an optical sensor, a temperature sensor, a chemical sensor, a gas sensor, and a biosensor.

12. The stretchable device of claim 1, wherein a respective electronic device of the plurality of electronic devices includes a silicon semiconductor, a III-V semiconductor, a telecommunication circuit, or a surface-mount device (SMD).

13. The stretchable device of claim 1, wherein a respective electronic device has a thickness in a range from 1 pm to 1 mm, and a size in a range from 10 pm to 10 mm along a dimension that is parallel to the first surface of the stretchable layer.

14. The stretchable device of claim 1, wherein the plurality of stretchable interconnects are formed from one or more materials selected from metal, carbon ink, silver ink, and conductive polymers.

15. The stretchable device of claim 1, wherein the stretchable device includes an energy storage device such as battery or a supercapacitor, or an display device such as a liquid crystal display device, an organic light-emitting electrochemical cell, a mini LED, a micro LED, or an active matrix organic light-emitting diode device.

16. A method of forming a stretchable device, comprising:

providing a rigid substrate including a first surface;

forming a support layer on the first surface of the rigid substrate, the support layer including a first set of patterns and a second set of patterns that interconnect with the first set of patterns respectively, wherein a plurality of stretchable interconnects are supported by the second set of patterns of the support layer respectively;

attaching a plurality of electronic devices to the first set of patterns of the support layer respectively, further including:

attaching a first side of a respective electronic device to a first surface of a corresponding pattern; and

electrically interconnecting the plurality of electronic devices via the plurality of stretchable interconnects respectively;

depositing a stretchable layer on top of the plurality of the electronic devices; and removing the rigid substrate to obtain the stretchable device including the stretchable layer, the support layer, and the plurality of electronic devices and the plurality of stretchable interconnects disposed between the stretchable layer and the support layer.

17. The method of claim 16, wherein the forming the support layer comprises:

depositing a first layer that covers the first surface of the rigid substrate;

patterning the first layer to form the support layer including the first set of patterns and the second set of patterns; and

after attaching the plurality of electronic devices to the first set of patterns, forming the plurality of stretchable interconnects on the second set of patterns of the support layer respectively.

18. The method of claim 16, wherein the forming the support layer comprises:

depositing the support layer including the first set of patterns and the second set of patterns on the first surface of the rigid substrate; and

19. The method of claim 16, wherein the forming the support layer comprises:

depositing a first layer that covers the first surface of the rigid substrate;

fabricating the plurality of stretchable interconnects on the first layer; and

patterning the first layer to form the first set of patterns corresponding to the plurality of electronic devices and the second set of patterns corresponding to the plurality of stretchable interconnects.

20. The method of claim 16, wherein the forming the support layer comprises:

depositing a first layer that covers the first surface of the rigid substrate;

attaching a plurality of electronic devices to on the first layer; and

patterning the first layer to form the first set of patterns corresponding to the plurality of electronic devices and the second set of patterns corresponding to the plurality of stretchable interconnects; and

fabricating the plurality of stretchable interconnects on the second set of patterns

21. The method of claim 16, wherein the forming the support layer comprises:

depositing a first layer that covers the first surface of the rigid substrate;

attaching a plurality of electronic devices and fabricating the plurality of stretchable interconnects on the first layer; and patterning the first layer to form the first set of patterns corresponding to the plurality of electronic devices and the second set of patterns corresponding to the plurality of stretchable interconnects.

22. The method of claim 16, wherein the rigid substrate is removed from the stretchable layer via laser ablation or mechanically peeling, or etching away a sacrificial layer using wet etching, plasma etching, laser ablation or a combination thereof, wherein the sacrificial layer is formed on the rigid substrate prior to forming the support layer.