WO2020018256A1

WO2020018256A1 - Stretchable electronics and monolithic integration method for fabricating the same

Info

Publication number: WO2020018256A1
Application number: PCT/US2019/039809
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: WO2020018255A1

Abstract

This application discloses a stretchable electronic device and a monolithic integration method for fabricating the same. The stretchable electronic device includes a first stretchable layer, a first support layer having a first set of patterns, and multiple subcircuits disposed between the first stretchable layer and the support layer. The subcircuits are directly fabricated on the first set of patterns respectively. The stretchable electronic device further includes multiple stretchable interconnects disposed on the first stretchable layer, each electrically interconnecting one subcircuit to another subcircuit respectively. The stretchable electronic device further includes an electrical connector including multiple first contacts connected to multiple second contacts of a first subcircuit respectively. The second contacts of the first subcircuit are attached to a first one of the first set of patterns that supports the first subcircuit. The electrical connector is configured to electrically connect the stretchable device to another electronic device.

Description

STRETCHABLE ELECTRONICS AND MONOLITHIC 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 monolithic integration processes for manufacturing the same.

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. A chiplet, which is an integrated circuit block that is part of a chip that consists of multiple such chiplets, is 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] In monolithic integrated circuits, different components and materials are directly fabricated on a sheet of glass substrate or a piece of wafer, thus bearing the advantages including reducing or eliminating the need for pick-and-place, bonding (wafer- and/or ball-bonding) and other assembly processes necessary in other types of assembly processes. Monolithic integration can be used for fabricating stretchable electronics. The method includes providing a support layer including support patterns, a rigid substrate, and directly fabricating electric circuits on the support patterns respectively. A stretchable layer, such as rubbers or thermoplastic elastomers, is then deposited on the support layer to cover the electric circuits. Further, the electric circuits are interconnected with conductive interconnects designed with certain stretchability. Based on the design, the electric circuits in the stretchable electronics can be used for computing, data storage, sensing, communicating and informative display.

[0007] In accordance with one aspect of this application, a stretchable electronic device includes a first stretchable layer. The stretchable electronic device further includes a first support layer having a first set of patterns. The stretchable electronic device also includes a plurality of subcircuits disposed between the first stretchable layer and the first support layer. The plurality of subcircuits are directly fabricated on the first set of patterns respectively. The stretchable electronic device also includes a plurality of stretchable interconnects disposed on the first stretchable layer. Each stretchable interconnect electrically interconnects one subcircuit to another subcircuit respectively. The stretchable electronic device further includes an electrical connector including a plurality of first contacts connected to a plurality of second contacts of a first subcircuit respectively. The plurality of second contacts of the first subcircuit are attached to a first one of the first set of patterns that supports the first subcircuit. The electrical connector is configured to electrically connect the stretchable device to another electronic device. [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, forming a first support layer on the first surface of the rigid substrate, and fabricating a plurality of subcircuits on the first support layer and a plurality of stretchable interconnects. Each stretchable interconnect electrically interconnects one subcircuit to another subcircuit respectively. The method further includes connecting an electrical connector to a first subcircuit of the plurality of subcircuits, which includes connecting a plurality of first contacts of the electrical connector to a plurality of second contacts of the first subcircuit. The plurality of second contacts of the first subcircuit are attached to the first support layer, and the electrical connector is configured to connect the stretchable device to another electronic device. The method also includes depositing a first stretchable layer to cover the plurality of the subcircuits and the plurality of stretchable interconnects, and removing the rigid substrate to obtain the stretchable device.

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-1F 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 3A-3C show embodiments of various support layer structures on rigid substrate for supporting electronic circuits of stretchable electronic devices in accordance with some implementations.

[0013] Figures 4A-4C illustrate an embodiment of forming a support layer and electronic circuits for a stretchable electronic device in accordance with some

implementations.

[0014] Figures 5A-5C illustrate an embodiment of forming a support layer and electronic circuits for a stretchable electronic device in accordance with some

implementations. [0015] Figures 6A-6C illustrate an embodiment of forming a support layer and electronic circuits for a stretchable electronic device in accordance with some

implementations.

[0016] Figures 7A-7D illustrate an example process for fabricating a stretchable electronic device including a support layer that is formed as discussed with references to Figures 4A-4C, 5A-5C, or 6A-6C, in accordance with some implementations.

[0017] Figures 8A-8I illustrate an example process for fabricating a stretchable electronic device including a support layer that is formed as discussed with references to Figures 4A-4C, 5A-5C, or 6A-6C, in accordance with some implementations.

[0018] Like reference numerals refer to corresponding parts throughout the several views of the drawings.

DESCRIPTION OF IMPLEMENTATIONS

[0019] Instead of starting from a stretchable substrate as used in the conventional methods, the process of the present disclosure starts from a rigid substrate. Then a support layer (e.g., polyimide) is patterned and used to support electronic circuits (e.g., subcircuits and optionally, the interconnects) from the bottom. Instead of transferring and bonding prefabricated electronic devices (e.g., chiplets), subcircuits and interconnects are

monolithically (e.g., directly) fabricated and integrated on top of the support layer during the process. An elastomer material is then coated on top of the interconnects and subcircuits, and the whole stack (including support layer, the interconnects and subcircuits, and the elastomer layer) is delaminated from the rigid substrate to obtain the stretchable electronic device.

[0020] The stretchable device and the method for fabricating the same provide numerous benefits including improved integration density, process compatibility, production yield, and improved cost-effectiveness. The process disclosed herein starts from a rigid substrate, and the stretchable layer (also referred to as elastomer material, flexible layer, elastomer layer, elastomer encapsulation, elastomer substrate, stretchable substrate) is introduced at the final stage. In addition, the process does not need to transfer prefabricated chiplets. Hence, the process can be adopted by the current semiconductor industry and display panel industry. Moreover, the support layer (e.g., the PI layer) is flexible, meanwhile provides robust mechanical support for the interconnects and the electronic circuits 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.

[0021] Figures 1 A-1F illustrate an example process for fabricating a stretchable electronic device 150 (e.g., Figure 1F) 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.

[0022] As shown in Figure 1 A, a rigid substrate 102 including a first surface 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 (not shown) is further formed on the rigid substrate 102 (e.g., before forming a support layer or support patterns). 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 or plasma etching or a

combination thereof.

[0023] In some embodiments as shown in Figure 1 A, a first support layer (e.g., including a plurality of support patterns 112) is formed (e.g., step 204, Figure 2) on the first surface of the rigid substrate 102. In some embodiments, the support layer (e.g., the support patterns) is formed of polyimide (PI). In some embodiments, the support layer is made of other suitable polymer material, such as polyethylene naphthalate (PEN), polyethylene terephthalate (PET), polyurethane (PU), polydimethylsiloxane (PDMS), polystyrene (PS), polyethersulfone (PES), polyethylene (PE), or polyvinyl chloride (PVC). In some

embodiments, the support layer includes a first set of patterns 112 that are disposed at discrete locations from each other on the rigid substrate 102 as shown in Figure 1 A. In some embodiments, the first set of patterns 112 are formed by lithography, printing, stamping, self- assembly, or any other suitable method.

[0024] In some embodiments as shown in Figure 1B, a plurality of electronic devices

122 (e.g., subcircuits) are directly fabricated (e.g., step 206, Figure 2) on the first set of support patterns 112 of the support layer. In some embodiments, a subcircuit 122 includes a plurality of electronic elements that are directly fabricated on a corresponding support pattern 112 of the first set of patterns (e.g., a PI island). In some embodiments, the subcircuit 122 is not pre-fabricated, and the subcircuit 122 is formed by fabricating a plurality of electronic elements directly on the corresponding support pattern. In some embodiments, a subcircuit 122 is a smaller unit than a pre-fabricated device or a circuit. In some embodiments, a first subcircuit l22a as shown in Figure 1B also includes a plurality of bonding pads 128 that are used to electrically connect the subcircuits of the stretchable device to another circuit board. In some embodiments, the bonding pads 128 are supported by the support pattern 112a of the corresponding subcircuit l22a.

[0025] In some embodiments as shown in Figure 1C, a plurality of stretchable interconnects 124 are directly fabricated (e.g., step 206, Figure 2) on the rigid substrate 102. In some embodiments, the plurality of stretchable interconnects are not supported by any support patterns. Instead, the plurality of stretchable interconnects are in direct contact with the rigid substrate 102. In some embodiments, each stretchable interconnect 124 electrically interconnects (e.g., step 206, Figure 2) one subcircuit l22a to another subcircuit l22b respectively. In some embodiments, the ends of the stretchable interconnects 124 are attached to (e.g., 125, Figure 1C) the first set of patterns 1 l2a and 1 l2b to form contact with the respective subcircuits l22a and l22b so as to connect the subcircuits 122 with each other. In some embodiments, the bonding pads 128 are further connected to an electrical connector including electrical wires 126 that are configured to electrically connect the stretchable device to other external circuits. In some embodiments, the electrical wires of the electrical connector 126 are concurrently formed when forming the stretchable interconnects. In some embodiments, the electrical wires of the electrical connector 126 are directly formed on the rigid substrate 102. That is, the electrical wires of the electrical connector 126 are not supported by any support pattern. In this case, the electrical wires may be able to detach from the rigid substrate 102 after forming the flexible layer 132 in the following steps. In some embodiments, the stretchable interconnects 124 are formed by depositing a metal layer followed by patterning the metal layer to form the stretchable interconnects 124 using a lithography or an etching process. In some embodiments, the stretchable interconnects 124 include one or more materials selected from metal, carbon ink, silver ink, and conductive polymers.

[0026] In some embodiments as shown in Figure 1C, an electrical connector 126 is connected (e.g., step 208, Figure 2) to a first subcircuit (e.g., subcircuit l02a, Figure 1C) of the plurality of subcircuits. In some embodiments, a plurality of first contacts of the electrical connector 126 are connected to (e.g., step 210, Figure 2) a plurality of the bonding pads 128 of the first subcircuit l22a. In some embodiments, the bonding pads 128 of the first subcircuit l22a are attached to the first support layer, e.g., the support pattern 1 l2a. In some embodiments, the electrical connector 126 is configured to electrically connect the stretchable device to another electronic device (not shown). In some embodiments, the electrical connector 126 is connected to a connector (e.g., a cable, a bonding flexible printed circuit, an HDMI cable, a VGA cable, a USB) that is used to connect to another device for certain functionalities.

[0027] In some embodiments as shown in Figure 1D, a stretchable layer 132 is deposited (e.g., 212, Figure 2) on top of the plurality of the subcircuits 122 and the plurality of stretchable interconnects 124. In some embodiments, a respective subcircuit 122 is sandwiched between the support pattern 112 and the stretchable layer 132 as shown in Figure 1D. 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 subcircuits 122 and the stretchable interconnects 124.

[0028] In some embodiments as shown in Figures 1E-1F, 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 that was deposited on the rigid substrate 102 prior to forming the support patterns 112.

[0029] In some embodiments as shown in Figure 1F, which is a flipped view of the stretchable layer 132, the subcircuits 122, and conductive interconnects 124 from Figure 1E, the stretchable device 150 includes the stretchable layer 132. In some embodiments, the stretchable device 150 further includes a support layer having a set of support patterns 112. For example, the support patterns 112 are discrete from each on the stretchable layer 132. In some embodiments, the stretchable device 150 also includes a plurality of subcircuits (not shown in Figure 1F due to flipped view blocked by the support patterns) disposed between the stretchable layer 132 and the support layer (e.g., support patterns 112). In some embodiments, the plurality of subcircuits 122 are directly fabricated on the support patterns 112 respectively. For example, a subcircuit includes a plurality of electronic elements that are directly fabricated on a corresponding pattern of the first set of patterns (e.g., a PI island). In some embodiments, a subcircuit includes a plurality of bonding pads 128 configured to provide electrical connection to other circuits. In some embodiments, the bonding pads 128 are also supported by the support pattern of the corresponding subcircuit. In some embodiments, the bonding pads 128 are further connected to electrical connector 126 (e.g., electrical wires) for connection to outer circuits. In some embodiments, the electrical connector 126 is not supported by any support pattern. In some other embodiments, the stretchable device further includes support patterns for the stretchable interconnects 124 and the electrical connector 126 (e.g., Figure 3C).

[0030] 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 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.

[0031] In some embodiments as shown in Figure 1F, a plurality of stretchable interconnects 124 are disposed on the stretchable layer 132. In some embodiments, each stretchable interconnect electrically interconnects one subcircuit to another subcircuit respectively. In some embodiments as shown in Figure 1F, the stretchable device 150 includes only the support patterns 112 for supporting the subcircuits, but without having any support patterns that support the stretchable interconnects 124 (e.g., this is also why the stretchable interconnects 124 are visible in the flipped view of Figure 1F).

[0032] In some embodiments, a respective subcircuit 122 includes pixel driving circuits formed from thin film transistors (TFT). In some embodiments, the subcircuit includes various sensors such as wearable sensors, gyro accelerators, diagnostic sensors, pressure sensors, optical sensors, temperature sensors, chemical sensors, gas sensors, and/or biosensors. In some embodiments, the subcircuit includes telecommunication circuit. In some embodiments, the subcircuit includes liquid crystal display device, organic light- emitting diode device, organic light-emitting electrochemical cell, mini light-emitting diode (LED), and/or micro LED. In some embodiments, the subcircuit includes a micro energy storage device, such as a battery or a supercapacitor. [0033] In some embodiments, the support patterns 112 includes polyimide (PI). In some embodiments, a respective support pattern 112 has a thickness in a range from 1 pm to 10 pm. In some embodiments as shown in Figures 1 A-1F, the support layer includes only the first set of patterns 112 configured to support the subcircuits 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.

[0034] In some embodiments, the plurality of stretchable interconnects 124 are coplanarly disposed on the stretchable layer 132 with the support patterns 112. In some embodiments, at least a portion of a respective stretchable interconnect overlaps with (e.g., attached to) a respective subcircuit to connect this subcircuit with another subcircuit.

[0035] 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.

[0036] In some embodiments, a respective subcircuit 122 directly fabricated on the corresponding support pattern. In some embodiments, a respective subcircuit 122 has predetermined functions. In some embodiments, the plurality of subcircuits 122 correspond to a plurality of pixel driving circuits configured to control display pixels of the stretchable device 150. In some embodiments, a respective subcircuit 122 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/or a biosensor. In some embodiments, a respective subcircuit 122 includes a silicon semiconductor, a III-V semiconductor, or a telecommunication circuit. In some

embodiments, the stretchable device 150 is a liquid crystal display device or an active matrix organic light-emitting diode (OLED) device.

[0037] In some embodiments, a respective subcircuit 122 has a thickness in a range from 1 pm to 1 mm. For example, a respective subcircuit 122 has a thickness of 3-5 pm. In another example, a respective subcircuit 122 has a thickness of no thicker than 1 mm. In some embodiments, a respective subcircuit 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, a respective subcircuit 122 has a square shape with a dimension of several tens of micrometers. 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.

[0038] Figures 3A-3C show embodiments of different types of support layer structures formed on the rigid substrate 102 for supporting electronic circuits of a stretchable electronic device in accordance with some implementations. In some embodiments as shown in Figure 3 A, only support patterns 112 configured to support the subcircuits 122 are formed on the rigid substrate 102, so that the final stretchable device will only include support pattern for supporting the subcircuits 122. In some embodiments, the bonding pads 128 are formed on a subcircuit and are supported by the corresponding support pattern that is configured to the support this subcircuit. In some embodiments, the stretchable interconnects 124 are not supported and are in direct contact with the rigid substrate 102. In some embodiments, the electrical connector 126 is also not supported by any support pattern. Although not shown, in some embodiments, the plurality of stretchable interconnects 124 are fabricated on the rigid substrate 102, before fabricating the plurality of subcircuits 122 on the support patterns 112.

[0039] In some other embodiments as shown in Figure 3B, a support layer 310 including a first set of support patterns 312 and a second set of support patterns 314 that interconnect the first set of support patterns 312 is formed on the rigid substrate 102. In some embodiments, the first set of support patterns 312 are configured to support the subcircuits 322 in the stretchable device, and the second set of support patterns 314 are configured to support the stretchable interconnects 324 in the stretchable device. As shown in Figure 3B, in some embodiments, the bonding pads 328 are formed on a subcircuit and are supported by the corresponding support pattern that is configured to the support this subcircuit. In some embodiments, the lateral shape and dimension of the plurality of stretchable interconnects 324 are a subset of the second set of patterns 314. That is, the stretchable interconnects only partially occupy the support patterns. In some embodiments, the plurality of stretchable interconnects 324 and the second set of patterns 314 have identical lateral shape and dimension. In some embodiments, the stretchable interconnects 324 are formed by depositing the stretchable interconnects 324 through a mask on the second set of patterns 314. In some embodiments, the stretchable interconnects 324 are formed by printing conductive ink on the second set of patterns 314. In some embodiments, the stretchable interconnects 324 are formed by depositing a metal layer followed by patterning the metal layer to form the stretchable interconnects 324 using a lithography or an etching process. In some

embodiments, the stretchable interconnects 324 include one or more materials selected from metal, carbon ink, silver ink, and conductive polymers. Although not shown, in some embodiments, the plurality of stretchable interconnects 324 are fabricated on the second set of patterns 314, before fabricating the plurality of subcircuits 322 on the first set of support patterns 312. In some embodiments, at least a portion of a respective stretchable interconnect 324 overlaps with (e.g., attached to) a respective subcircuit 322 to connect this subcircuit with another electronic device.

[0040] In some other embodiments as shown in Figure 3C, in addition to the first and second support patterns 312 and 314, the support layer 310 formed on the rigid substrate 102 further includes a set of contact support patterns 330 configured to support the electrical connector 326. In some embodiments, the connector 326 includes a plurality of stretchable wires 332 (e.g., interconnects formed in the same process as the stretchable interconnects) that connects a subcircuit to a plurality of electrical contacts 334 (e.g., bonding pads, or tabs). The electrical contacts 334 may be further used to connect to external circuits. As shown in Figure 3C, the contact support patterns 330 are configured to support the stretchable wires 332 and the electrical contacts 334.

[0041] Figures 4A-4C illustrate a process of forming a support layer and electronic circuits for a stretchable electronic device in accordance with some implementations. In some embodiments as shown in Figure 4A, forming the support layer comprises: patterning the first support layer to form a first set of patterns 412 and a second set of patterns 414 interconnected with the first set of patterns in the support layer. In some embodiments, the first and second support patterns are formed of polyimide (PI). In some embodiments, the first set of patterns 412 are configured to support the plurality of subcircuits 422 respectively. In some embodiments, the first set of patterns 412 are directly deposited on the first surface of the rigid substrate. In some embodiments, the first and second set of support patterns are formed on the rigid substrate 102 by lithography, direct printing, screen printing, depositing using a shadow mask, or any other suitable method.

[0042] In some embodiments as shown in Figure 4B, after forming the support patterns, a plurality of subcircuits 422 are fabricated on the first set of patterns 412 respectively. In some embodiments, the subcircuits 422 are directly fabricated on the support patterns 412 respectively. In some embodiments, bonding pads 428 are also formed on a subcircuit.

[0043] In some embodiments as shown in Figure 4C, after fabricating the subcircuits, the plurality of stretchable interconnects 424 are fabricated on the second set of patterns 414 respectively. Although not shown, in some embodiments, the plurality of stretchable interconnects 424 are fabricated on the second set of patterns 414, before fabricating the plurality of subcircuits 422 on the first set of support patterns 412. In some embodiments, at least a portion of a respective stretchable interconnect 424 overlaps with (e.g., attached to) a respective subcircuit 422 to connect this subcircuit with another electronic device.

[0044] Figures 5A-5C illustrate a process of forming a support layer and electronic circuits for a stretchable electronic device in accordance with some implementations. In some embodiments as shown in Figure 5A, forming the support layer comprises: depositing a continuous support layer 510 on the rigid substrate 102. Then a plurality of subcircuits 522 are directly fabricated on the support layer 510. In some embodiments, a plurality of bonding pads 528 are also formed in a subcircuit during this process.

[0045] In some embodiments as shown in Figure 5B, after fabricating the plurality of subcircuits 522 on the second side of the first support layer 510 (e.g., first side in contact with the rigid substrate 102), the method further comprises patterning the first support layer 510 to form a first set of patterns 512 that support the plurality of subcircuits 522 respectively. In some embodiments, patterning the support layer 510 further generates a second set of patterns 514 that interconnect with the first set of patterns 512.

[0046] In some embodiments as shown in Figure 5C, the plurality of stretchable interconnects 524 are fabricated on the second set of patterns 514 respectively. In some embodiments, the second set of patterns 514 are optional, as the stretchable interconnects 524 can be either supported or unsupported.

[0047] Figures 6A-6C illustrate a process of forming a support layer and electronic circuits for a stretchable electronic device in accordance with some implementations. In some embodiments as shown in Figure 6A, forming the support layer comprises: depositing a continuous support layer 610 on the rigid substrate 102. Then a plurality of subcircuits 622 are directly fabricated on the support layer 610. In some embodiments, a plurality of bonding pads 628 are also formed in a subcircuit during this process.

[0048] In some embodiments as shown in Figure 6B, after fabricating the plurality of subcircuits 622 on the second side of the first support layer 610 (e.g., first side in contact with the rigid substrate 102), the method further comprises fabricating the plurality of stretchable interconnects 624 on the second side of the first support layer 610. Although not shown, in some embodiments, the plurality of stretchable interconnects 624 are fabricated on the second side of the first support layer 610 (e.g., first side in contact with the rigid substrate 102), before fabricating the plurality of subcircuits 622 on the second side of the first support layer 610 In some embodiments, at least a portion of a respective stretchable interconnect 624 overlaps with (e.g., attached to) a respective subcircuit 622 to connect this subcircuit with another electronic device.

[0049] In some embodiments as shown in Figure 6C, patterning (e.g., lithography) the support layer 610 to form a first set of patterns 612 configured to support the plurality of subcircuits 622 and a second set of patterns 614 configured to support the plurality of stretchable interconnects 624 In some embodiments, the second set of patterns 614 are optional, as the stretchable interconnects can be either supported or unsupported.

[0050] There are multiple ways to form the support layer including the first set of patterns for supporting the electronic devices, and, optionally, 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, optionally form the second set of patterns in the support layer, attach the plurality of electronic devices to the first set of patterns respectively, and attach the plurality of stretchable interconnects to the second set of patterns respectively or directly to the rigid substrate can vary. In some embodiments, the support layer may be patterned at any stage during the process of forming the stretchable device. In some embodiments, the support layer may have both the first and second sets of patterns. In some alternative embodiments, the support layer only has the first set of patterns, and the plurality of stretchable interconnects are directly formed on the rigid substrate.

[0051] In some embodiments, forming the first support layer comprise: patterning the first support layer to form a first set of patterns and a second set of patterns interconnected with the first set of patterns in the support layer. In some embodiments, the plurality of subcircuits are fabricated on the first set of patterns respectively, and the plurality of stretchable interconnects are fabricated on the second set of patterns respectively.

[0052] In some embodiments, forming the first support layer comprise: patterning the first support layer to form a first set of patterns. In some embodiments, the plurality of subcircuits are fabricated on the first set of patterns respectively, and the plurality of stretchable interconnects are directly fabricated on the first surface of the rigid substrate.

[0053] In some embodiments, the first support layer includes a first set of patterns to support the plurality of subcircuits respectively. In some embodiments, the first set of patterns are directly deposited on the first surface of the rigid substrate. [0054] In some embodiments, after fabricating the plurality of subcircuits on the second side of the first support layer, the first support layer is patterned to form a first set of patterns that support the plurality of subcircuits respectively and a second set of patterns that interconnect with the first set of patterns. In some embodiments, the plurality of stretchable interconnects are fabricated on the second set of patterns respectively.

[0055] In some embodiments, after fabricating the plurality of subcircuits on the second side of the first support layer, the first support layer is patterned to form a first set of patterns that support the plurality of subcircuits respectively. In some embodiments, the plurality of stretchable interconnects are directly formed on the first surface of the rigid substrate.

[0056] In some embodiments, after fabricating the plurality of interconnects on the second side of the first support layer, the first support layer is patterned to form a first set of patterns that support the plurality of subcircuits respectively and a second set of patterns that interconnect with the first set of patterns. In some embodiments, the plurality of subcircuits are fabricated on the first set of patterns respectively.

[0057] In some embodiments, after fabricating the plurality of subcircuits and the plurality of stretchable interconnects, the first support layer is patterned to form a first set of patterns corresponding to the plurality of subcircuits and a second set of patterns

corresponding to the plurality of stretchable interconnects.

[0058] Figures 7A-7D illustrate an example process for fabricating a stretchable electronic device (e.g., stretchable electronic device 750, Figure 7D) based on the structure formed on the rigid substrate as discussed with references to Figures 3A-3C, 4A-4C, 5A-5C, or 6A-6C respectively, in accordance with some implementations. In some embodiments as shown in Figure 7A, a support layer including a first set of support patterns 712 and a second set of support patterns 714 are formed on the rigid substrate 102. In some embodiments, a plurality of subcircuits 722 are formed on the first set of support patterns 712 respectively, and a plurality of stretchable interconnects 724 are formed on the second set of support patterns 714 respectively. In some embodiments, bonding pads 728 are also formed in a subcircuit and are used for connecting to an electric connector to electrically connect to an external circuit. In some embodiments, Figure 7A is substantially similar to the structure discussed with referene to Figure 4C, 5C, and 6C.

[0059] In some embodiments as shown in Figure 7B, an electrical connector 730, such as a flexible printed circuit (FPC) board or FPC cable (e.g., an HDMI cable, a VGA cable) or a chip on film (COF), is bonded to the bonding pads 728. In some embodiments, the FPC cable 730 is used to electrically connect to an external device. In some

embodiments, the bonding pads 728 are supported by the support pattern for the

corresponding subcircuit, but there is no connector support pattern to support the electrical connector 730. In some embodiments, there is connector support pattern to support the electrical connector 730.

[0060] In some embodiments as shown in Figure 7C, after forming the FPC cable

730, a stretchable layer (e.g., an elastomer layer) is deposited on the rigid substrate 102 to cover the subcircuits 722 and the stretchable interconnects 724. In some embodiments, the stretchable layer also covers a first portion 733 of the FPC cable 730 that overlaps with (e.g., supported by, in contact with) the rigid substrate 102, and a second portion 724 of the FPC cable 730 that extends out of the rigid substrate 102 is not covered the stretchable layer. In some embodiments as shown in Figure 7C, a portion 733 of the electrical connector 730 is sandwiched between the stretchable layer 732 and the rigid substrate 102. Another portion 734 (e.g., adjacent to the portion 733) of the electrical connector 730 extends out from the stretchable layer 732 and can be used to connect to another circuit or device.

[0061] In some embodiments as shown in Figure 7D (e.g., flipped view of the stretchable layer 732 deposited on the rigid substrate 102), after depositing the stretchable layer 732, the rigid substrate 102 is removed from the stretchable layer by laser ablation, mechanical peeling, dissolving the sacrificial layer, or any other suitable method as discussed elsewhere herein. In some embodiments, the stretchable device 750 is obtained after detaching the rigid substrate 102 from the stretchable layer 732.

[0062] Figures 8A-8I illustrate an example process for fabricating a stretchable electronic device including a support layer that is based on the structure formed on the rigid substrate as discussed with references to Figures 3A-3C, 4A-4C, 5A-5C, or 6A-6C respectively, in accordance with some implementations. In some embodiments as shown in Figure 8A, a support layer including a first set of support patterns 812 and a second set of support patterns 814 are formed on the rigid substrate 102. In some embodiments, a plurality of subcircuits 822 are formed on the first set of support patterns 812 respectively, and a plurality of stretchable interconnects 824 are formed on the second set of support patterns 814 respectively. In some embodiments, bonding pads 828 are also formed in a subcircuit and are used for connecting to an electric connector to electrically connect to an external circuit. In some embodiments, Figure 8A is substantially similar to the structure discussed with reference to Figure 4C, 5C, and 6C. .

[0063] In some embodiments as shown in Figure 8B, after patterning (e.g., via lithography) the first support layer (e.g., support layer 610, Figure 6B) to form a first set of patterns 812 to support the plurality of subcircuits 822 respectively and a second set of patterns 814 to support the plurality of stretchable interconnects 824 respectively, and before connecting an electrical connector to a first subcircuit, the process further includes depositing a second support layer 840 on the plurality of subcircuits 822 and the plurality of stretchable interconnects 824. In some embodiments, the second support layer 840 is formed of a material (e.g., polyimide) that is substantially similar to that of the first support layer. In some embodiments, the second support layer 840 has a thickness in a range from 1 pm to 10 pm.

[0064] In some embodiments as shown in Figure 8C, the process further includes patterning the second support layer 840 to form a third set of patterns 842 interconnected with a fourth set of patterns 844. In some embodiments, the plurality of subcircuits 822 are sandwiched between the first set of patterns 812 and the third set of patterns 842 respectively. In some embodiments, and the plurality of stretchable interconnects 824 are sandwiched between the second set of patterns 814 and the fourth set of patterns 844 respectively. In some embodiments, the first subcircuit 822a is sandwiched between a first support pattern 812a of the first set of patterns 812 and a second support pattern 842a from the third set of patterns 842. In some embodiments, the plurality of second contacts (e.g., bonding pads 828) of the first subcircuit 822a are attached to the first support pattern 812a. In some

embodiments, the second support pattern 842a includes an opening 846 that exposes the plurality of second contacts 828 of the first subcircuit 822a for connecting the plurality of second contacts 828 to the plurality of first contacts of an electrical connector (e.g., electrical connector 826, Figure 8D). In some embodiments, the second support layer 840 including the support patterns 842 and 844 provides an improved support and robust protection to the plurality of subcircuits 822 and the plurality of stretchable interconnects 824 in the final stretchable device. In some embodiments, the first set of patterns 812 and the second set of patterns 814 are patterned together with the third set of patterns 842 and the fourth set of patterns 844. And then the opening 846 is opened.

[0065] In some embodiments as shown in Figure 8D, the electrical connector 826 is electrically connected to the bonding pads 828 as shown in Figure 8C. In some embodiments, the electrical connector 826 includes a cable, a bonding flexible printed circuit (FPC) cable, an HDMI cable, a VGA cable, a USB or any other suitable connector that is used to connect to another device for certain functionalities.

[0066] In some embodiments as shown in 8E, a first stretchable layer 832 is deposited on top of the rigid substrate 102 to cover the third set of support patterns 842 and the fourth set of support patterns 844. In some embodiments, the stretchable layer 832 are formed by depositing an elastomer polymer, such as natural rubber, synthetic rubber or thermoplastic elastomer (TPE). In some embodiments, the stretchable layer 832 covers a first portion of the FPC cable 826 that overlaps with (e.g., supported by, in contact with) the rigid substrate 102, and a second portion of the FPC cable 826 that extends out of the rigid substrate 102 is not covered the stretchable layer.

[0067] In some embodiments as shown in 8F, after depositing the stretchable layer

832, the rigid substrate 102 is removed from the stretchable layer by laser ablation, mechanical peeling, dissolving the sacrificial layer, or any other suitable method as discussed elsewhere herein. In some embodiments, the stretchable device 850 including double support layers is obtained after detaching the rigid substrate 102 from the stretchable layer 832.

[0068] In some embodiments as discussed herein, the stretchable device 850 includes a second support layer disposed between the first stretchable layer 832 and the plurality of subcircuits 822 and the plurality of stretchable interconnects 824. In some embodiments, the second support layer including a third set of patterns 842 interconnected with a fourth set of patterns 844, wherein the plurality of subcircuits 822 are sandwiched between the first set of patterns 812 and the third set of patterns respectively 842, and the plurality of stretchable interconnects 824 are sandwiched between the second set of patterns 814 and the fourth set of patterns 844 respectively.

[0069] In some embodiments as discussed with reference to Figure 8C, the first subcircuit 822a is sandwiched between the first support pattern 8l2a and a second support pattern 842a from the third set of patterns 842. In some embodiments, the second support pattern 842a includes an opening 846 that exposes the plurality of second contacts (e.g., bonding pads) 828 of the first subcircuit 822a for connecting the plurality of second contacts 828 to the plurality of first contacts of the electrical connector (e.g., electrical connector 826, Figure 8D). [0070] In some embodiments as shown in Figure 8G, the stretchable device 850 is flipped, such that the first support layer including the first set of support patterns 812 and the second set of support patterns 814 are placed on top.

[0071] In some embodiments as shown in Figure 8H, after removing the rigid substrate 102 (e.g., 8E to 8F) the process further includes depositing a second stretchable layer 860 on the first stretchable layer 832 to cover the patterned first support layer including the first set of support patterns 812 and the second set of support patterns 814.

[0072] In some embodiments, the stretchable layer 860 are formed by depositing an elastomer polymer, such as natural rubber, synthetic rubber or thermoplastic elastomer (TPE). In some embodiments, the stretchable layer 860 covers a first portion of the FPC cable 826 that overlaps with (e.g., supported by, in contact with) the first stretchable layer 832, and a second portion of the FPC cable 826 that extends out of sandwiched structure formed by the first stretchable layer 832 and the second stretchable layer 860. In some embodiments, a stretchable device 870 including double support layers and double stretchable layers are formed.

[0073] Figure 81 is a cross sectional view of the stretchable device 870 including double support layers and double stretchable layers. In some embodiments, the stretchable device 870 includes a first stretchable layer 832, and a support layer including a third set of support patterns 842 and a fourth set of support patterns 844 disposed on the first stretchable layer. In some embodiments, a plurality of subcircuits 822 and a plurality of stretchable interconnects 824 are disposed on the third set of support patterns 842 and the fourth set of support patterns 844 respectively. In some embodiments, the plurality of subcircuits 822 are sandwiched between and supported by a first set of support patterns 812 and the third set of support patterns 842. The plurality of stretchable interconnects 824 are sandwiched between and supported by a second set of support patterns 814 and the fourth set of support patterns 844.

[0074] In some embodiments, the stretchable device 870 further includes a second stretchable layer 860 disposed opposite to the first support layer 832 to cover the first set of support patterns 812 and the second set of support patterns 814. In some embodiments, the first and second stretchable layer 832 and 860 are configured to sandwich the double support layers, the plurality of subcircuits, and the plurality of stretchable interconnects in between to provide improved robustness, flexibility, and mechanical integrity. In some embodiments, the stretchable device 870 further includes an electrical connector 825 with a first portion that is sandwiched between the first and second stretchable layers and have direct contact with bonding pads on the first subcircuit. The rest of the electrical connector 825 extends out of the stretchable layers and configured to connect to another electronic device (not shown).

[0075] 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 flexible substrate devices that can be implemented in this application. One of ordinary skill in the art would recognize various ways to form a flexible electronic device based on the devices and methods as described herein.

[0076] 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.

[0077] 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.

[0078] 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.

[0079] 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.

[0080] 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.

[0081] 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 first stretchable layer;

a first support layer having a first set of patterns;

a plurality of subcircuits disposed between the first stretchable layer and the support layer, wherein the plurality of subcircuits are directly fabricated on the first set of patterns respectively;

a plurality of stretchable interconnects disposed on the first stretchable layer, each stretchable interconnect electrically interconnecting one subcircuit to another subcircuit respectively; and

an electrical connector including a plurality of first contacts connected to a plurality of second contacts of a first subcircuit respectively, wherein the plurality of second contacts of the first subcircuit are attached to a first one of the first set of patterns that supports the first subcircuit, and the electrical connector is configured to electrically connect the stretchable device to another electronic device.

2. The stretchable device of claim 1, further comprising:

a second stretchable layer disposed opposite to the first support layer, wherein the first and second stretchable layers are configured to sandwich the support layer, the plurality of subcircuits, and the plurality of stretchable interconnects in between.

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

4. The stretchable device of claim 1, wherein the electrical connector includes a plurality of bonding pads for electrically connecting the subcircuits of the stretchable device to another external circuit board.

5. The stretchable device of claim 1, wherein the first support layer further comprises a contact support pattern configure to support the electrical connector.

6. The stretchable device of claim 1, wherein the electrical connector is connected to the first subcircuit of the plurality of subcircuits by interconnects.

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

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

9. The stretchable device of claim 7, wherein the plurality of stretchable interconnects and the second set of patterns have identical lateral shape and dimension.

10. The stretchable device of claim 7, further comprising:

a second support layer disposed between the first stretchable layer and the plurality of subcircuits and the plurality of stretchable interconnects, the second support layer including a third set of patterns interconnected with a fourth set of patterns, wherein the plurality of subcircuits are sandwiched between the first set of patterns and the third set of patterns respectively, and the plurality of stretchable interconnects are sandwiched between the second set of patterns and the fourth set of patterns respectively.

11. The stretchable device of claim 10, wherein the first subcircuit is sandwiched between the first support pattern and a second support pattern from the third set of patterns, the second support pattern including an opening that exposes the plurality of second contacts of the first subcircuit for connecting the plurality of second contacts to the plurality of first contacts of the electrical connector.

12. The stretchable device of claim 1, wherein the plurality of subcircuits includes pixel driving circuits formed from thin film transistors (TFT), sensors such as wearable sensors, gyro accelerators, diagnostic sensors, pressure sensors, optical sensors, temperature sensors, chemical sensors, gas sensors, and/or biosensors, telecommunication circuits, liquid crystal display devices, organic light-emitting diode devices, organic light-emitting electrochemical cells, mini light-emitting diodes (LEDs), and/or micro LEDs, micro energy storage devices such as a battery or a supercapacitor.

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

providing a rigid substrate including a first surface;

forming a first support layer on the first surface of the rigid substrate;

fabricating a plurality of subcircuits on the first support layer and a plurality of stretchable interconnects, each stretchable interconnect electrically interconnecting one subcircuit to another subcircuit respectively;

connecting an electrical connector to a first subcircuit of the plurality of subcircuits, further including:

connecting a plurality of first contacts of the electrical connector to a plurality of second contacts of the first subcircuit, wherein the plurality of second contacts of the first subcircuit are attached to the first support layer, and wherein the electrical connector is configured to connect the stretchable device to another electronic device;

depositing a first stretchable layer to cover the plurality of the subcircuits and the plurality of stretchable interconnects; and

removing the rigid substrate to obtain the stretchable device.

14. The method of claim 13, wherein the forming the first support layer comprise:

patterning the first support layer to form a first set of patterns and a second set of patterns interconnected with the first set of patterns in the support layer,

wherein the plurality of subcircuits are fabricated on the first set of patterns respectively, and the plurality of stretchable interconnects are fabricated on the second set of patterns respectively.

15. The method of claim 13, wherein the forming the first support layer comprise:

patterning the first support layer to form a first set of patterns, wherein the plurality of subcircuits are fabricated on the first set of patterns respectively, and the plurality of stretchable interconnects are directly fabricated on the first surface of the rigid substrate.

16. The method of claim 13, wherein the first support layer includes a first set of patterns to support the plurality of subcircuits respectively, and wherein the first set of patterns are directly deposited on the first surface of the rigid substrate.

17. The method of claim 13, further comprising:

after fabricating the plurality of subcircuits on the second side of the first support layer:

patterning the first support layer to form a first set of patterns that support the plurality of subcircuits respectively and a second set of patterns that interconnect with the first set of patterns,

wherein the plurality of stretchable interconnects are fabricated on the second set of patterns respectively.

18. The method of claim 13, further comprising:

patterning the first support layer to form a first set of patterns that support the plurality of subcircuits respectively, wherein the plurality of stretchable interconnects are directly formed on the first surface of the rigid substrate.

19. The method of claim 13, further comprising:

after fabricating the plurality of interconnects on the second side of the first support layer:

wherein the plurality of subcircuits are fabricated on the first set of patterns respectively.

20. The method of claim 13, further comprising:

after fabricating the plurality of subcircuits and the plurality of stretchable

interconnects:

patterning the first support layer to form a first set of patterns corresponding to the plurality of subcircuits and a second set of patterns corresponding to the plurality of stretchable interconnects.

21. The method of claim 13, wherein the first support layer includes a first set of patterns and the plurality of subcircuits are fabricated on the first set of patterns respectively.

22. The method of claim 13, further comprising:

patterning the first support layer to form a first set of patterns to support the plurality of subcircuits respectively and a second set of patterns to support the plurality of stretchable interconnects respectively;

before connecting the electrical connector to the first subcircuit, depositing a second support layer on the plurality of subcircuits and the plurality of stretchable interconnects; patterning the second support layer to form a third set of patterns interconnected with a fourth set of patterns, wherein:

the plurality of subcircuits are sandwiched between the first set of patterns and the third set of patterns respectively, and the plurality of stretchable interconnects are sandwiched between the second set of patterns and the fourth set of patterns respectively, the first subcircuit is sandwiched between a first support pattern of the first set of patterns and a second support pattern from the third set of patterns, the plurality of second contacts of the first subcircuit are attached to the first support pattern, and

the second support pattern includes an opening that exposes the plurality of second contacts of the first subcircuit for connecting the plurality of second contacts to the plurality of first contacts of the electrical connector.

23. The method of claim 13, further comprising:

after removing the rigid substrate e, depositing a second stretchable layer on the patterned first support layer.

24. The method of claim 13, wherein the rigid substrate is removed from the support layer via laser ablation , mechanical 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.