Method for manufacturing electronic device, and method for manufacturing stretchable display

Abstract

This method for manufacturing an electronic device includes: a step for forming an element layer (4) on a first surface (3a) of a base layer (3) that contains a resin; a step for dividing the element layer (4) into a plurality of elements (4d) by forming separation grooves (4e) in the element layer (4) on the first surface (3a); a step for removing portions of the base layer (3), which overlap with the separation grooves (4e), partway through the layer thickness to leave connection parts (3c); a step for having the plurality of elements (4d) supported by a first support substrate (8), which is positioned on the front surface side of the plurality of elements (4d); a step for removing the connection parts (3c); a step for having the plurality of elements (4d) supported by a second support substrate (2), which is positioned on the back surface side of the plurality of elements (4d); and a step for separating the first support substrate (8) from the plurality of elements (4d).

Description

Method for manufacturing an electronic device and method for manufacturing a stretchable display

[0001] The present disclosure relates to a method for manufacturing an electronic device in which electronic elements are attached to a support substrate, and a method for manufacturing a stretchable display.

[0002] A method for manufacturing an electronic device is known in which an electronic element is attached to a support substrate while being manufactured (see Patent Document 1).

[0003] Japanese Patent Publication No. 2014-048619

[0004] When forming stretchable devices (such as stretchable displays (hereinafter referred to as stretchable displays) and stretchable sensors) that are currently being researched and developed, a resin (such as PI (Polyimide)) substrate that serves as the base for the device elements is first formed on a glass substrate that serves as a carrier substrate. After elements are formed on the resin substrate, the resin substrate is patterned into a stretchable shape. Next, the resin substrate is peeled off from the glass substrate, and the device elements are transferred to another stretchable substrate, thereby forming a stretchable device.

[0005] However, as device resolution increases and the size of device elements decreases, there is a possibility that the device elements may peel off from the carrier substrate during the formation process due to cleaning or the like, or that stress from peeling may cause disconnections during the process of peeling the resin substrate from the glass substrate in the laser lift-off (LLO) process, resulting in defects.

[0006] A method for manufacturing an electronic device according to one embodiment of the present disclosure includes the steps of forming an element layer on a first surface of a base layer containing a resin, dividing the element layer into a plurality of elements by forming separation grooves in the element layer on the first surface, removing a portion of the base layer that overlaps with the separation grooves to the middle of its thickness to leave a connecting portion, supporting the plurality of elements on a first support substrate located on the front side of the plurality of elements, removing the connecting portion, supporting the plurality of elements on a second support substrate located on the back side of the plurality of elements, and separating the first support substrate from the plurality of elements.

[0007] A method for manufacturing a stretchable display according to one aspect of the present disclosure includes a method for manufacturing an electronic device according to one aspect of the present disclosure.

[0008] According to one aspect of the present disclosure, it is possible to provide a method for manufacturing an electronic device and a method for manufacturing a stretchable display that can reduce defects.

[0009] 1 is a plan view of a stretchable display according to embodiment 1. FIG. 2 is an enlarged view of a portion A shown in FIG. 1. FIG. 3 is a cross-sectional view taken along line III-III shown in FIG. 2. FIG. 4 is a cross-sectional view showing a manufacturing method of a stretchable display according to embodiment 2. FIG. 5 is a cross-sectional view showing a manufacturing method of a stretchable display according to embodiment 2. FIG. 6 is a cross-sectional view showing a manufacturing method of a stretchable display according to embodiment 2. FIG. 7 is a cross-sectional view showing a manufacturing method of a stretchable display according to embodiment 2. FIG. 8 is a cross-sectional view showing a manufacturing method of a stretchable display according to embodiment 2. FIG. 9 is a cross-sectional view showing a manufacturing method of a stretchable display according to embodiment 2. FIG. 10 is a cross-sectional view showing a manufacturing method of a stretchable display according to embodiment 2. FIG. 11 is a cross-sectional view showing a manufacturing method of a stretchable display according to embodiment 2. FIG. 12 is a cross-sectional view showing a manufacturing method of a stretchable display according to embodiment 2. FIG. 13 is a cross-sectional view showing a manufacturing method of a stretchable display according to embodiment 2. FIG. 14 is a cross-sectional view showing a manufacturing method of a stretchable display according to embodiment 3. FIG. 15 is a cross-sectional view showing a manufacturing method of a stretchable display according to embodiment 3. FIG. 16 is a cross-sectional view showing a manufacturing method of a stretchable display according to embodiment 3. FIG. 17 is a cross-sectional view showing a manufacturing method of a stretchable display according to embodiment 3.

[0010] (Embodiment 1) Fig. 1 is a plan view of a stretchable display 1 according to embodiment 1. Fig. 2 is an enlarged view of the X portion shown in Fig. 1. Fig. 3 is a cross-sectional view taken along line III-III shown in Fig. 2.

[0011] The stretchable display (electronic device) 1 includes a second support substrate 2, which is a stretchable resin substrate. A base layer 3 is formed on the second support substrate 2. An insulating film 22 and a TFT (Thin Film Transistor) layer 23 for driving elements are formed in this order on the base layer 3. The base layer 3 is patterned into a plurality of element regions 4a arranged in a matrix and a plurality of wiring regions 4b that electrically connect adjacent element regions 4a. Wiring 4g formed in each wiring region 4b is arranged in a meandering manner and has a shape that includes one or more bends 4c.

[0012] Three stripe-shaped elements 4d are formed parallel to each other in each element region 4a. The three elements 4d are, for example, an element that emits red light, an element that emits green light, and an element that emits blue light.

[0013] The second support substrate 2 is a resin substrate having elasticity, such as polyurethane. The element regions 4a are regions where light-emitting elements such as TFT circuits, OLEDs (organic light-emitting diodes), LEDs (light-emitting diodes), optical sensors, and capacitance touch sensors are formed, and are element portions that do not deform (stretch). The regions between each element region 4a are regions that do deform (stretch), and are portions where wiring 4g is arranged. On the base layer 3, a SiO ２ An insulating film 22 made of a material such as a metal, and a TFT layer 23 for driving the element 4d are provided. The wiring 4g includes a metal wiring.

[0014] The elements 4d are light-emitting elements such as OLEDs and LEDs. The elements 4d may also be optical sensors or capacitance touch sensors. When the elements 4d are light-emitting elements, the elements 4d may include an organic light-emitting layer or a quantum dot light-emitting layer. Each of the elements 4d includes a light-emitting body and a pixel circuit. After forming an insulating film 22 on the base layer 3, a TFT layer 23 is formed, and the elements 4d are formed on the TFT layer 23.

[0015] Second Embodiment A method for manufacturing the stretchable display 1 will now be described.

[0016] 4 to 13 are cross-sectional views showing a manufacturing method of the stretchable display 1 according to embodiment 2. Components similar to those described above are given the same reference numerals, and detailed description thereof will not be repeated.

[0017] First, as shown in Fig. 4, a resin is applied to a carrier substrate 10 made of a glass substrate to form a base layer 3. The resin is, for example, PI. Then, as shown in Fig. 5, an element layer 4 is formed on a first surface 3e of the base layer 3.

[0018] The element layer 4 includes a TFT and corresponds to the TFT layer 23 in FIG.

[0019] Next, as shown in Figure 6, separation grooves 4e are formed in the element layer 4 on the first surface 3e of the base layer 3, thereby dividing the element layer 4 into a plurality of elements 4d and an insulating film 25. That is, the element layer 4 is patterned into the shapes of the elements 4d and the insulating film 25 to be divided, thereby exposing the first surface 3e of the base layer 3. The elements 4d include a plurality of TFTs. However, for simplicity of illustration, only one TFT is depicted in Figure 6 and other figures.

[0020] The configuration of FIG. 3 of embodiment 1 is an example in which an element 4d including a TFT layer 23 and a light-emitting layer is formed on a base layer 3, and the configuration of FIG. 6 of embodiment 2 is an example in which the element 4d including the light-emitting layer is omitted from the configuration of embodiment 1, and the TFT layer 23 is shown as only one TFT as element 4d. The element 4d shown in FIG. 6 corresponds to the TFT layer 23 shown in FIG. 3.

[0021] 7, the portions of the base layer 3 that overlap with the separation grooves 4e are removed by dry etching to a depth corresponding to the depth h1 of the layer thickness h, thereby forming the connecting portions 3c. These connecting portions 3c are formed by dry etching. In this manner, the base layer 3 is patterned by dry etching along the shapes of the elements 4d to be separated. At this time, the grooves are formed in the base layer 3 so that the base layer 3 is not completely patterned, and the entire base layer 3 is left connected by the connecting portions 3c.

[0022] In the TFT process for forming the elements 4d including TFTs, cleaning processes using pure water or solvents and drying processes are repeated. The PI that constitutes the resin layer of the base layer 3 loses adhesion to the glass that constitutes the carrier substrate 10 due to moisture absorption. Therefore, if the separation grooves 4e penetrate all the way to the carrier substrate 10 (without the connecting portions 3c), the elements 4d become more likely to peel off from the carrier substrate 10 as the size of the elements 4d becomes smaller, and there is a possibility that the base layer 3 will peel off from the carrier substrate 10 during the TFT process.

[0023] In contrast to this, in this embodiment, the PI of the base layer 3 is formed with a connecting portion 3c having a thickness of (h-h1), which is the layer thickness h minus the depth h1, and does not penetrate to the surface of the carrier substrate 10. Therefore, even if the size of the element 4d becomes small, the entire base layer 3 is connected by the connecting portion 3c, so that it is possible to prevent the element 4d from easily peeling off from the carrier substrate 10.

[0024] 8, a first support substrate 8, which serves as a transfer substrate, is prepared on the front surface side of the plurality of elements 4d, and the plurality of elements 4d is supported on the first support substrate 8. The first support substrate 8 is a film substrate for transferring the plurality of elements 4d, and is attached to the surface of the plurality of elements 4d.

[0025] 9, a UV pulse laser 9a is irradiated onto the interface 11 between the carrier substrate 10 and the base layer 3 to weaken the adhesion between the carrier substrate 10 and the base layer 3. That is, the UV pulse laser 9a is irradiated onto the interface 11 between the carrier substrate 10 and the base layer 3.

[0026] 10 , the carrier substrate 10 is separated from the base layer 3. In this manner, the plurality of elements 4d and the base layer 3 are disposed above the carrier substrate 10, and after the plurality of elements 4d are supported by the first support substrate 8, the carrier substrate 10 is separated from the base layer 3.

[0027] In the laser lift-off (LLO) process shown in FIGS. 9 and 10 , the UV pulse laser 9 a is irradiated from the back surface of the carrier substrate 10, so if there are small scratches or stains on the back surface of the carrier substrate 10, they may cast a shadow and create a portion of the interface 11 where the UV pulse laser 9 a does not sufficiently hit, which may result in failure to separate the base layer 3 and the carrier substrate 10.

[0028] Such changes in the adhesion between the base layer 3 and the carrier substrate 10 due to small scratches or stains do not cause problems in a normal LLO peeling process (where the base layer 3 is large in size), but when the base layer 3 is separated into small pieces corresponding to multiple elements 4d, they can cause peeling failure.

[0029] In this embodiment, the entire base layer 3 is connected by the connecting portion 3c during the LLO peeling process. Therefore, even if such a small scratch or stain causes a change in adhesion, it does not cause a problem, just like in a normal LLO peeling process.

[0030] 11 , a UV pulse laser 9b is irradiated from the side of the base layer 3 opposite the elements 4d to remove the connecting portions 3c and divide the base layer 3. When removing the connecting portions 3c, parts of the base layer 3 that overlap with each element 4d are also removed. The irradiation energy conditions for the UV pulse laser 9b are set so that the connecting portions 3c of the base layer 3 are removed while parts of the base layer 3 that overlap with each element 4d remain. The UV pulse lasers 9a and 9b are pulse lasers with a wavelength in the ultraviolet range.

[0031] 12 , a second support substrate 2 is prepared on the back surface side of the plurality of elements 4d, and the plurality of elements 4d are supported on the second support substrate 2. The second support substrate 2 is a stretchable resin substrate. For example, the second support substrate 2 made of a stretchable material such as polyurethane is attached to the base layer 3.

[0032] 13, the first support substrate 8 is separated from the plurality of elements 4d. After the first support substrate 8 is separated from the plurality of elements 4d in this manner, a portion of the base layer 3 remains between each element 4d and the second support substrate 2.

[0033] In this way, by removing the first support substrate 8 used in the transfer from the element 4d, the stretchable stretchable display 1 is completed.

[0034] Although the manufacturing method of the stretchable display 1 has been described as an example, the present disclosure is not limited thereto. This embodiment can be applied to any manufacturing method of an electronic device in which a transfer process is repeated multiple times. For example, this embodiment can be applied to a manufacturing method of a mini LED or a micro LED in which a transfer process is repeated multiple times. Furthermore, the wiring 4g does not need to be formed simultaneously with the elements 4d. After transfer, the wiring 4g may be formed in a separate process to connect the element regions 4a to each other.

[0035] 14 to 23 are cross-sectional views showing a manufacturing method of a stretchable display 1 according to embodiment 3. Components similar to those described above are given the same reference numerals, and detailed description thereof will not be repeated.

[0036] First, as shown in Fig. 14, a base layer 3A is formed on a carrier substrate 10 made of a glass substrate. The base layer 3A is composed of a first resin layer 5, an inorganic layer 6, and a second resin layer 7, arranged in this order from the bottom layer closest to the carrier substrate 10. The first resin layer 5 and the second resin layer 7 contain, for example, PI. In this way, the base layer 3A has a laminated structure in which an inorganic layer 6 such as an insulating film is sandwiched between two layers of PI.

[0037] Then, as shown in FIG. 15, an element layer 4 including TFTs and the like is formed on the first surface 3e of the base layer 3A.

[0038] Next, as shown in FIG. 16, separation grooves 4e are formed in the element layer 4 on the first surface 3e of the base layer 3A, thereby dividing the element layer 4 into a plurality of elements 4d.

[0039] 17, the second resin layer 7 is removed from the portion of the base layer 3A that is located below the separation groove 4e. That is, the portion of the base layer 3A that overlaps with the separation groove 4e is removed to a position corresponding to the depth h1, leaving the connecting portion 3c.

[0040] The base layer 3A is formed by interposing SiO between the first resin layer 5 and the second resin layer 7. ２Therefore, when removing the base layer 3A, the inorganic layer 6 acts as an etching stopper, and only the second resin layer 7 can be removed, and the second resin layer 7 can be removed with a uniform thickness.

[0041] Then, as shown in FIG. 18, a first support substrate 8, which serves as a transfer substrate, is attached to the front surface of the element 4d.

[0042] Next, as shown in Figure 19, a UV pulse laser 9a is irradiated onto the interface 11 between the carrier substrate 10 and the first resin layer 5 of the base layer 3A from the second surface 3b located opposite the first surface 3e of the base layer 3A.

[0043] Thereafter, as shown in FIG. 20, the carrier substrate 10 is removed from the base layer 3A.

[0044] 21 , a UV pulse laser 9b is irradiated from the second surface 3b of the base layer 3A to remove the first resin layer 5 and the inorganic layer 6. In this manner, the base layer 3A is separated. This removal using the UV pulse laser 9b removes the entire first resin layer 5, and also removes the inorganic layer 6 located at the connecting portions 3c together with the first resin layer 5.

[0045] In a stretchable device, if the thickness of the base layer is non-uniform, stress will concentrate in that area, which may damage the device formed on the base layer. In the manufacturing method for a stretchable display according to this embodiment, the thickness of the base layer 3A can be made more uniform, thereby preventing damage to the element 4d.

[0046] 22, the plurality of elements 4d are supported on a second support substrate 2 prepared on the back surface side of the plurality of elements 4d. The second support substrate 2 is a stretchable resin substrate.

[0047] 23, the first support substrate 8 is separated from the plurality of elements 4d. After the first support substrate 8 is separated from the plurality of elements 4d, a part of the second resin layer 7 and a part of the inorganic layer 6 remain between each element 4d and the second support substrate 2.

[0048] The present disclosure is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present disclosure. Furthermore, new technical features can be formed by combining the technical means disclosed in each embodiment.

[0049] REFERENCE SIGNS LIST 1 Stretchable display (electronic device) 2 Second support substrate (second support substrate) 3 Base layer 3b Second surface 3c Connecting portion 3d Overlapping portion 3e First surface 4 Element layer 4a Element region 4b Wiring region 4c Bent portion 4d Element 4e Separation groove 4f Semiconductor film 4g Wiring 5 First resin layer 6 Inorganic layer 7 Second resin layer 8 First support substrate (first support substrate) 9a Laser 9b Laser 10 Carrier substrate 11 Interface

Claims

1. A method for manufacturing an electronic device, comprising the steps of: forming an element layer on a first surface of a base layer containing resin; dividing the element layer into a plurality of elements by forming separation grooves in the element layer on the first surface; removing a portion of the base layer that overlaps with the separation grooves to halfway through its layer thickness to leave a connecting portion; supporting the plurality of elements on a first support substrate located on the front side of the plurality of elements; removing the connecting portion; supporting the plurality of elements on a second support substrate located on the back side of the plurality of elements; and isolating the first support substrate from the plurality of elements.

2. The method for manufacturing an electronic device according to claim 1, further comprising the step of irradiating the base layer with a laser from a second surface located opposite the first surface to remove the connecting portion.

3. The method for manufacturing an electronic device according to claim 2, wherein when removing the connecting portions, the portions of the base layer that overlap each element are removed to the middle of their layer thickness.

4. The method for producing an electronic device according to any one of claims 1 to 3, wherein the isolation groove is formed by dry etching.

5. A method for manufacturing an electronic device according to any one of claims 1 to 4, wherein the base layer is disposed above a carrier substrate, and after the first support substrate supports the plurality of elements, the carrier substrate is separated from the base layer.

6. The method for manufacturing an electronic device according to claim 5, further comprising irradiating an interface between the carrier substrate and the base layer with a laser to separate the carrier substrate from the base layer.

7. The method for manufacturing an electronic device according to any one of claims 1 to 6, wherein the element layer includes a plurality of element regions corresponding to the plurality of elements, respectively, and wiring that electrically connects the plurality of element regions.

8. A method for manufacturing an electronic device according to any one of claims 1 to 7, wherein after the first support substrate is separated from the plurality of elements, a portion of the base layer remains between each element and the second support substrate.

9. The method for manufacturing an electronic device according to any one of claims 1 to 8, wherein the base layer is formed by arranging, from the bottom side, a first resin layer, an inorganic layer, and a second resin layer in this order.

10. The method for producing an electronic device according to claim 9, wherein the portion of the base layer located under the separation groove is removed to a thickness corresponding to that of the second resin layer.

11. The method for manufacturing an electronic device described in claim 10, further comprising irradiating the base layer with a laser from a second surface opposite the first surface to remove the first resin layer and the inorganic layer at the connecting portion.

12. The method for producing an electronic device according to claim 11, wherein the first resin layer is entirely removed when the connecting portion is removed.

13. The method for manufacturing an electronic device described in claim 11, wherein after the first support substrate is separated from the plurality of elements, a portion of the second resin layer and a portion of the inorganic layer remain between each element and the second support substrate.

14. The method for manufacturing an electronic device according to claim 2 or 6, wherein the laser is a pulsed laser having a wavelength in the ultraviolet range.

15. The method for producing an electronic device according to any one of claims 1 to 14, wherein the element layer includes a semiconductor film.

16. The method for producing an electronic device according to any one of claims 1 to 15, wherein each of the plurality of elements includes a light emitter and a pixel circuit.

17. The method for producing an electronic device according to any one of claims 1 to 16, wherein the second support substrate is a stretchable resin substrate.

18. The method for manufacturing an electronic device according to claim 7, wherein the wiring has a shape including one or more bent portions.

19. A method for producing a stretchable display, comprising the method for producing an electronic device according to claim 16.

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