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

Abstract

This method for manufacturing an electronic device includes: a step for forming a base layer (3) in which a first resin layer (5), an inorganic film pattern (12), and a second resin layer (5) are arranged in this order from the lower layer side; a step for forming a plurality of elements (4d) on a first surface (3a) of the base layer (3) so that the plurality of elements (4d) overlap with the inorganic film pattern (12) in a plan view; a step for having the plurality of elements (4d) supported by a first support substrate (8) that is positioned on the front surface side of the plurality of elements (4d); a step for removing the first resin layer (5); a step for patterning the second resin layer (5) using the inorganic film pattern (12) as a mask; a step for having the plurality of elements (4d) supported by a second support substrate (2) that 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 invention 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 using a 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 a base layer having a first resin layer, an inorganic film pattern, and a second resin layer arranged in this order from the bottom up; forming a plurality of elements on a first surface of the base layer so as to overlap the inorganic film pattern in a planar view; supporting the plurality of elements on a first support substrate located on the front side of the plurality of elements; removing the first resin layer; patterning the second resin layer using the inorganic film pattern as a mask; 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 2. 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. FIG. 18 is a cross-sectional view showing a manufacturing method of a stretchable display according to embodiment 3. 10A and 10B are cross-sectional views showing a method for manufacturing a stretchable display according to embodiment 3. FIG. 10B are cross-sectional views showing a method for manufacturing 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 14 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 first resin layer 5. The resin is, for example, PI. Then, as shown in Fig. 5, an inorganic film pattern 12 is formed on the first resin layer 5 by photolithography. This inorganic film pattern 12 is preferably made of metal. The inorganic film pattern 12 is preferably made of SiO ２ 6, a second resin layer 7 is formed on the first resin layer 5 so as to cover the inorganic film pattern 12. The second resin layer 7 is made of, for example, PI. In this manner, the base layer 3, in which the first resin layer 5, the inorganic film pattern 12, and the second resin layer 7 are arranged in this order from the bottom, is formed on the carrier substrate 10.

[0018] 7, a plurality of elements 4d are formed on the first surface 3e of the base layer 3 so as to overlap the inorganic film pattern 12 in a plan view. Each element 4d includes a plurality of TFTs. However, for simplicity of illustration, only one TFT is depicted in FIG. 7 and other figures. The element 4d corresponds to the TFT layer 23 in FIG. 3.

[0019] In the TFT process for forming multiple elements 4d, cleaning processes using pure water or solvents and drying processes are repeated. The PI of the base layer 3 loses adhesion to the glass due to moisture absorption. Therefore, if the size of the base layer 3 is reduced to match the size of the elements 4d, it becomes more likely to peel off from the carrier substrate 10, and there is a possibility that the base layer 3 will peel off from the carrier substrate 10 during the TFT process.

[0020] In this embodiment, the size of the base layer 3 is large regardless of the size of the element 4d, and therefore the base layer 3 does not peel off.

[0021] 8, a first support substrate 8 that 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 transfer, and is attached to the surfaces of the plurality of elements 4d.

[0022] 9 and 10 , a UV pulse laser 9 is irradiated onto the interface 11 between the carrier substrate 10 and the base layer 3, thereby weakening the adhesion between the carrier substrate 10 and the base layer 3 and separating the carrier substrate 10 from the base layer 3. In this manner, the plurality of elements 4d and the base layer 3 are formed above the carrier substrate 10, and after the plurality of elements 4d are supported on the first support substrate 8, the carrier substrate 10 is separated from the base layer 3.

[0023] In the laser lift-off (LLO) process shown in FIGS. 9 and 10 , the UV pulse laser 9 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 will cast a shadow, causing a portion where the UV pulse laser 9 does not sufficiently hit the interface 11, and the base layer 3 and the carrier substrate 10 may not be separated properly.

[0024] Such changes in the adhesion between the base layer 3 and the carrier substrate 10 due to small scratches or stains do not pose a problem in a normal LLO peeling process (where the base layer 3 is large in size), but can cause peeling failure when the base layer 3 is separated into small pieces corresponding to multiple elements 4d.

[0025] In this embodiment, the base layer 3 is not divided into small pieces corresponding to the plurality of elements 4d during the LLO peeling process, so even if such small scratches or stains cause changes in adhesion, this does not pose a problem, just like in the normal LLO peeling process.

[0026] Thereafter, as shown in FIG. 11, the base layer 3 is wet-etched from the second surface 3b located on the opposite side to the first surface 3e, thereby removing the first resin layer 5.

[0027] 12, a portion of the second resin layer 7 is removed by wet etching. That is, the second resin layer 7 is patterned using the inorganic film pattern 12 as a mask. Although the second resin layer 7 is patterned by wet etching, the second resin layer 7 may also be removed by dry etching such as oxygen plasma. Alternatively, patterning may be performed by combining wet etching and dry etching.

[0028] 13, a second support substrate 2 is prepared on the back surface side of the plurality of elements 4d, and the plurality of elements 4d is supported on the second support substrate 2. The second support substrate 2 is a stretchable resin substrate such as polyurethane.

[0029] 14 , 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 the inorganic film pattern 12 remain between the plurality of elements 4d and the second support substrate 2. In this way, the stretchable display 1 is completed by removing the first support substrate 8, which is a transfer substrate.

[0030] 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 element 4d. After transfer, the wiring 4g may be formed in a separate process to connect the element region 4a.

[0031] 15 to 26 are cross-sectional views showing a manufacturing method of a stretchable display 1A according to embodiment 3. Components similar to those described above are given the same reference numerals, and detailed description thereof will not be repeated.

[0032] First, as shown in FIG. 15 , a resin is applied to a carrier substrate 10 made of a glass substrate to form a first resin layer 5. Then, as shown in FIG. 16 , an insulating film 6 is formed on the first resin layer 5. After that, an inorganic film pattern 12 is formed on the insulating film 6 by photolithography. Next, as shown in FIG. 17 , a second resin layer 7 is formed on the insulating film 6 so as to cover the inorganic film pattern 12. In this manner, a base layer 3A is formed on the carrier substrate 10, in which the first resin layer 5, insulating film 6, inorganic film pattern 12, and second resin layer 7 are arranged in this order from bottom to top. In this manner, the base layer 3A includes a planar insulating film 6 between the first resin layer 5 and the inorganic film pattern 12.

[0033] Thereafter, as shown in FIG. 18, a plurality of elements 4d are formed on the first surface 3e of the base layer 3A so as to overlap the inorganic film pattern 12 in a plan view.

[0034] Then, as shown in FIG. 19, a first support substrate 8 is prepared on the surface side of the plurality of elements 4d, and the first support substrate 8 is attached to the surface of the plurality of elements 4d to support them.

[0035] 20 and 21 , the interface 11 between the carrier substrate 10 and the base layer 3A is irradiated with a UV pulse laser 9 to separate the carrier substrate 10 from the base layer 3A. In this manner, the plurality of elements 4d and the base layer 3A are formed above the carrier substrate 10, and after the plurality of elements 4d are supported on the first support substrate 8, the carrier substrate 10 is separated from the base layer 3A.

[0036] 22, the base layer 3A is wet-etched from the second surface 3b located opposite to the first surface 3e to remove the first resin layer 5. When removing the first resin layer 5, the insulating film 6 functions as an etching stopper.

[0037] 23, the insulating film 6 is removed by wet etching with hydrofluoric acid, etc. In this way, the insulating film 6 is removed after the first resin layer 5 is removed.

[0038] 24, the inorganic film pattern 12 is used as a mask to pattern the second resin layer 7. The second resin layer 7 is patterned by dry etching.

[0039] 25, a second support substrate 2 is prepared on the back surface side of the plurality of elements 4d, and the plurality of elements 4d is supported on the second support substrate 2. The second support substrate 2 is a stretchable resin substrate such as polyurethane.

[0040] 26 , 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 the inorganic film pattern 12 remain between the plurality of elements 4d and the second support substrate 2. By removing the first support substrate 8 in this manner, the stretchable display 1A is completed.

[0041] In the third embodiment, in addition to the inorganic film pattern 12 made of, for example, metal, an insulating film 6 is formed between the first resin layer 5 and the second resin layer 7 on the first resin layer 5 side of the inorganic film pattern 12 .

[0042] The peel-and-transfer process shown in FIGS. 18 to 21 is the same as that of embodiment 2, but the first resin layer 5 shown in FIG. 22 can be wet-etched at a high etching rate. If the etching rate is too high, the second resin layer 7 may also be etched. In this case, the side etching of the second resin layer 7 becomes large, resulting in the size of the second resin layer 7 being smaller than the size of the element 4d. In this case, there is a high possibility that the element 4d will peel off from the second resin layer 7 during the peel-off process shown in FIG. 26. Therefore, the insulating film 6 is used to stop the wet etching of the first resin layer 5. Furthermore, when the insulating film 6 is removed by wet etching as shown in FIG. 23, the second resin layer 7 is not etched.

[0043] 24 , the exposed portion of the second resin layer 7 from the inorganic film pattern 12 is removed by dry etching, thereby patterning the second resin layer 7. Dry etching makes it easy to control the etching rate and shape depending on the conditions, so the second resin layer 7 can be stably patterned.

[0044] 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.

[0045] REFERENCE SIGNS LIST 1 Stretchable display (electronic device) 2 Second support substrate (second support substrate) 3 Base layer 3b Second surface 3e First surface 4 Element layer 4a Element region 4b Wiring region 4c Bent portion 4d Element 4f Semiconductor film 5 First resin layer 6 Insulating film 7 Second resin layer 8 First support substrate (first support substrate) 9 Laser 10 Carrier substrate 11 Interface 12 Inorganic film pattern

Claims

1. A method for manufacturing an electronic device, comprising the steps of: forming a base layer having a first resin layer, an inorganic film pattern, and a second resin layer arranged in this order from the bottom side; forming a plurality of elements on a first surface of the base layer so as to overlap the inorganic film pattern in a planar view; supporting the plurality of elements on a first support substrate located on the front side of the plurality of elements; removing the first resin layer; patterning the second resin layer using the inorganic film pattern as a mask; 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 removing the first resin layer by wet etching the base layer from a second surface located opposite the first surface.

3. The method for producing an electronic device according to claim 2, wherein the second resin layer is patterned by wet etching.

4. The method for producing an electronic device according to claim 2, wherein the second resin layer is patterned by dry etching.

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

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. A method for manufacturing an electronic device described in any one of claims 1 to 6, wherein after the first support substrate is separated from the plurality of elements, a portion of the second resin layer and the inorganic pattern remain between the plurality of elements and the second support substrate.

8. The method for manufacturing an electronic device according to any one of claims 1 to 7, wherein the base layer includes a planar insulating film between the first resin layer and the inorganic film pattern.

9. The method for manufacturing an electronic device according to claim 8, wherein the inorganic film pattern is made of metal.

10. The method for producing an electronic device according to claim 8, wherein the insulating film functions as an etching stopper when the first resin layer is removed.

11. The method for producing an electronic device according to claim 10, wherein the insulating film is removed after the first resin layer is removed.

12. The method for producing an electronic device according to claim 11, wherein the insulating film is removed by wet etching.

13. The method for producing an electronic device according to claim 9, wherein the second resin layer is patterned by dry etching.

14. The method for producing an electronic device according to any one of claims 1 to 12, wherein each of the plurality of elements includes a semiconductor film.

15. The method for producing an electronic device according to any one of claims 1 to 14, wherein each of the plurality of elements includes a light emitter and a pixel circuit.

16. The method for producing an electronic device according to any one of claims 1 to 15, wherein the second support substrate is a stretchable resin substrate.

17. A method for producing a stretchable display, comprising the method for producing an electronic device according to claim 15.

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