JP2023161706A - Electronic device - Google Patents

Abstract

To provide a flexible electronic device having high reliability and being able to expand and contract.SOLUTION: An aspect of the present invention is an electronic device in which a plurality of elements are arranged in a first direction at first intervals and arranged in a second direction at second intervals, and the elements are connected in the first direction with first wires 110 and connected in the second direction with second wires. The elements are formed in a first part 101 of a first organic insulating film 10. The first wire 110 is formed in a second part 111 of the first organic insulating film 10. The first wire 110 includes a first part that is linear near the element and a second part that is curved in the other part. In the first part that is linear, the first wire 110 is disconnected. The first wire 110 is connected by a first wire bonding 90 at the disconnected part.SELECTED DRAWING: Figure 11

Description

The present invention relates to an electronic device having flexibility and stretchability.

There is an increasing demand for electronic devices that are flexible or stretchable. Applications of such a flexible electronic device include, for example, attaching it to the case of an electronic device having a curved surface, attaching it to a display medium having a curved surface, and attaching it to a human body as a sensor. Examples of the elements include sensors such as touch sensors, temperature sensors, pressure sensors, and acceleration sensors, as well as light emitting elements and light valves that constitute various display devices.

In sensor devices, scanning lines and signal lines are used to control each element. In flexible electronic devices, it is necessary for the device to withstand bending and expansion/contraction. Patent Document 1 describes that the scanning line and the video signal line are made to meander (hereinafter also referred to as meander wiring) to create a structure that can withstand bending and expansion/contraction.

JP 2021-106199 Publication

By forming the scanning lines and signal lines into a meandering structure, a certain degree of resistance to expansion/contraction or bending of the flexible electronic device can be obtained. However, if the device is expanded, contracted or curved, even if the scanning lines and signal lines have a meandering structure, it is not possible to apply uniform stress to the entire wiring.

That is, when the device is expanded, contracted, or bent, rupture occurs at the portion where the stress is greatest. Conversely, by taking measures to improve the structure of the portions where stress is most likely to be applied, it is possible to improve the resistance of the flexible electronic device to bending and expansion/contraction.

An object of the present invention is to take measures against the structure of parts that are susceptible to stress when a flexible electronic device is expanded, contracted, or curved, and to create a flexible electronic device that is highly resistant to expansion, contraction, and curving, and therefore has high reliability. The goal is to realize the device.

The present invention achieves the above object, and representative means are as follows.

(1) A plurality of elements are arranged at a first interval in a first direction and at a second interval in a second direction, and the plurality of elements are arranged by a first wiring in the first direction. and connected in a second direction by a second wire, the element being formed in a first portion of a first organic insulating film, and the first wire comprising: The first wiring is formed on a second portion of the first organic insulating film, and has a straight first portion near the element and a second curved portion. the first wiring is divided in the linear first portion, and the first wiring is connected in the divided portion by a first wire bonding. electronic equipment.

(2) The electronic device according to (1), wherein the first organic insulating film is formed along the element and the first wiring.

(3) The first portion and the second portion of the first organic insulating film are separated at the portion where the first wiring is separated. The electronic device described in .

(4) The electronic device according to (1), wherein the curved portion that is the second portion of the first wiring has a meander structure.

(5) The second wiring is formed in a third portion of the first organic insulating film, and the second wiring is connected to a linear third portion near the element and other portions. , the second wiring has a curved fourth part, the second wiring is divided in the straight third part, and the second wiring has a second wire in the divided part. An electronic device characterized by being connected by bonding.
(6) A plurality of elements are arranged at a first interval in a first direction and at a second interval in a second direction, and the plurality of elements are arranged by a first wiring in the first direction. and connected in a second direction by a second wire, the element being formed in a first portion of a first organic insulating film, and the first wire comprising: The first wiring is formed in a second portion of the first organic insulating film, and has a straight first portion near the element and a second curved portion. An electronic device comprising: a wire bonding formed in the first direction in the linear first portion of the first wiring.

FIG. 2 is a plan view of the flexible electronic device. 2 is a sectional view taken along line AA in FIG. 1. FIG. FIG. 3 is a plan view showing a wiring shape in an active region. 4 is a sectional view taken along line BB in FIG. 3. FIG. 4 is a sectional view taken along the line CC in FIG. 3. FIG. FIG. 2 is a plan view showing an element and its surroundings. 7 is a sectional view taken along line DD in FIG. 6. FIG. FIG. 2 is a plan view showing a part of the base material on which wiring and elements are formed. FIG. 2 is a plan view showing a region where large stress occurs when the flexible electronic device is stretched in the lateral direction (x direction). FIG. 10 is a plan view showing that a disconnection occurs in the wiring in a region where a large stress is applied, as shown in FIG. 9; 1 is a plan view showing a schematic configuration of Example 1. FIG. 12 is a sectional view taken along line EE in FIG. 11. FIG. 12 is a sectional view taken along line EE in FIG. 11 when stretched in the x direction. FIG. 2 is a plan view showing a specific configuration of a characteristic portion of Example 1. FIG. 13 is a cross-sectional view in the x direction of FIG. 12. FIG. FIG. 16 is a cross-sectional view showing an initial process for realizing the configuration of FIG. 15; FIG. 17 is a cross-sectional view showing a process following FIG. 16; FIG. 18 is a cross-sectional view showing a process following FIG. 17; 19 is a cross-sectional view showing a process following FIG. 18. FIG. FIG. 20 is a cross-sectional view showing a process following FIG. 19; 21 is a cross-sectional view showing a process following FIG. 20. FIG. FIG. 22 is a cross-sectional view showing a process following FIG. 21; 23 is a cross-sectional view showing a process following FIG. 22. FIG. 24 is a cross-sectional view showing a process following FIG. 23. FIG. FIG. 3 is a plan view showing Example 2. 26 is a sectional view in the x direction of FIG. 25. FIG. FIG. 7 is a plan view showing Example 3; 28 is a sectional view in the x direction of FIG. 27. FIG. FIG. 4 is a plan view showing Example 4; 30 is a sectional view in the x direction of FIG. 29. FIG. FIG. 7 is a plan view showing Example 5. 32 is a sectional view in the x direction of FIG. 31. FIG. FIG. 7 is a plan view showing problems of Example 6. FIG. 6 is a plan view showing Example 6. 35 is a cross-sectional view in the y direction of FIG. 34. FIG. 36 is a cross-sectional view of an intermediate process for forming the structure of FIG. 35. FIG. FIG. 37 is a cross-sectional view showing a state in which wire bonding is performed on the configuration of FIG. 36;

The contents of the present invention will be explained in detail below using Examples.

FIG. 1 is a plan view of a flexible electronic device 1 in Example 1. Although the flexible electronic device 1 shown in FIG. 1 has a flat plate shape as a whole, it can be curved in the z direction or stretched on the xy plane. The elongation rate at break, that is, the elongation rate until the flexible electronic device 1 breaks, differs depending on the material that constitutes the flexible electronic device 1, but if the flexible electronic device 1 is mainly made of organic materials with high ductility, the elongation rate is 30%. %, and in some cases, 60%. On the other hand, if a relatively large amount of inorganic material is used, the elongation rate is about 10% to 15%.

In FIG. 1, the flexible electronic device 1 has an active region 5 occupying a large area. In the active region 5, electronic elements 100 are arranged in a matrix. As the electronic element 100, for example, a sensor, a semiconductor element, an actuator, etc. can be arranged. As the sensor, for example, an optical sensor that detects visible light or infrared light, a temperature sensor, a pressure sensor, a touch sensor, etc. can be arranged. As the semiconductor element, for example, a light emitting element, a light receiving element, a diode, a transistor, etc. can be arranged. As the actuator, for example, a piezo element or the like can be used.

Each electronic element 100 is connected to a scanning line 110 and a signal line 120. The scanning lines 110 extend in the horizontal direction (the x direction, which corresponds to the first direction) and are arranged in the vertical direction (the y direction, which corresponds to the second direction). They extend in the direction (y direction) and are arranged in the horizontal direction (x direction). In FIG. 1, both the scanning line 110 and the signal line 120 extend in a straight line, but this is to avoid complicating the diagram; in reality, as shown in FIG. 110 extends in the horizontal direction, and the signal line 120 extends in the vertical direction.

In FIG. 1, drive circuits 115 and 125 and a terminal region 6 are arranged outside the active region 5. A scanning line drive circuit 115 is arranged on both sides of the active region 5 in the x direction, and a power supply circuit 130 for supplying power to the electronic element 100 is located above the active region 5 in the y direction. A signal line drive circuit 125 is arranged on the lower side in the direction. Further below the signal line drive circuit 125, a terminal region 6 is arranged. A flexible wiring board 150 is connected to the terminal area 6 for supplying power and signals to the flexible electronic device 1 and for transmitting signals to the outside.

FIG. 2 is a sectional view taken along line AA in FIG. FIG. 2 is a schematic cross-sectional view. In FIG. 2, the electronic device 100, scanning line 110, signal line 120, etc. described in FIG. 1 are present in the device layer 2. In other words, the function of the flexible electronic device 1 exists in the element layer 2. This element layer 2 is covered with an upper protective layer 3 from above and a lower protective layer 4 from below. Both the upper protective layer 3 and the lower protective layer 4 are formed of a material that is easily elastically deformed, that is, has a small Young's modulus.

In FIG. 2, the active region 5, drive circuits 115, 125, etc. are covered with the upper protective layer 3 and the lower protective layer 4, but the end portions of the element layer 2 are not covered with the upper protective layer 3. There is a portion, and this portion serves as the terminal area 6. The terminal area 6 is protected only by the lower protective layer 4. A flexible wiring board 150 is connected to the terminal area 6 .

FIG. 3 is a plan view of the display area 5. FIG. 3 shows the main components of the element layer 2 shown in FIG. That is, the element layer 2 shown in FIG. 2 does not exist as a single planar substrate, but has a meandering structure 102 in which a scanning line 110 and a signal line 120 are formed, as shown in FIG. It is composed of a base material 10 in which an element region 101 is formed at the intersection of a line 110 and a signal line 120, and has a so-called mesh-like structure.

In FIG. 3, the meandering structure 102 and the element region 101 located at the intersection are made of resin such as polyimide. This resin is used as a base material 10, and scanning lines 110, signal lines 120, elements 100, etc. are formed thereon. In FIG. 3, a diamond-shaped element 100 exists in an element region 101. The reason for this configuration is to reduce stress on each component even when the flexible electronic device 1 is stretched.

In FIG. 3, the diameter of the diamond-shaped element 100 in the x direction and the diameter in the y direction are each 100 μm, for example. The pitch of the element 100 in the x direction and the pitch in the y direction is, for example, 250 μm. Further, the width of the base material 10 including the scanning line 110, video signal line 120, etc. in the meandering structure 102 is, for example, 30 μm.

FIG. 4 is a cross-sectional view taken along line BB in FIG. 3, and is a cross-sectional view of the meandering structure including the scanning line 110. In FIG. 4, a first organic insulating film 20 is formed on a base material 10. As shown in FIG. A scanning line 110 is formed on the first organic insulating film 20 . A second organic insulating film 30 is formed to cover the scanning line 110. A plan view of the meandering structure 102 including the scanning line 110 in FIG. 3 represents the planar shape of the base material 10.

The base material 10, the first organic insulating film 20, and the second organic insulating film 30 are made of polyimide, for example. Polyimide has excellent properties such as mechanical strength and heat resistance, so it is suitable as the base material 10 of the scanning line 110 and the signal line 120. That is, when the flexible electronic device 1 is stretched, the polyimide absorbs the stress generated in the meandering structure, so the stress applied to the scanning lines 110 and the like formed of metal is reduced.

The scanning line 110 has, for example, a TAT (Ti-Al-Ti, titanium-aluminum-titanium) structure. In the three-layer structure, Al is primarily responsible for electrical conductivity, and Ti is used to protect Al or improve bonding with other wiring. In addition to this, the material of the scanning line 110 can take various configurations depending on the use of the flexible electronic device 1, such as MoW (molybdenum-tungsten alloy).

As shown in FIG. 3, the meandering structure 102 (hereinafter also simply referred to as the scanning line 110) having the scanning line 110 has an unstable shape, so it is fixed with protective layers (3 and 4 shown in FIG. 2) from above and below. . First, a meandering structure in which the scanning lines 110 are formed is covered with a first buffer layer 40 made of an organic material. It is covered with a first protective layer 50 made of an organic material. A second buffer layer 60 made of an organic material is arranged on the lower surface of the base material 10, and a second protective layer 70 made of an organic material is formed thereunder.

In this way, the meandering structure including the scanning line 110 has an unstable shape, but since it is fixed from above and below by the buffer layers 40 and 60 and the protective layers 50 and 70, the shape can be kept stable. . By the way, since the electronic device of the present invention is a flexible electronic device, it needs to be able to expand and contract in response to external tensile stress. Therefore, it is desirable that the buffer layers 40, 60 and the protective layers 50, 70 sandwiching the polyimide meandering structure be made of a material that is easier to stretch than polyimide, that is, a material that has a smaller Young's modulus. Examples of such materials include resins such as acrylic, urethane, epoxy, and silicone.

FIG. 5 is a cross-sectional view taken along the line CC in FIG. 3, and is a cross-sectional view of a meandering structure including the signal line 120. In the meander structure of FIG. 5, a first organic insulating film 20 and a second organic insulating film 30 are successively formed on a base material 10 and patterned. Further, a signal line 120 is formed on the second organic insulating film 30. In the first embodiment, the signal line 120 has the same material as the scanning line, that is, a TAT (Ti-Al-Ti) structure, but it may be made of other materials depending on the use of the flexible electronic device. The other structure is the same as the cross-sectional shape of the scanning line 110 portion explained in FIG.

FIG. 6 is a plan view of the element region 101. The outer shape of the element region 101 is also defined by the base material 10 made of polyimide. The element region 101 in FIG. 6 has a rhombus shape, but since the top of the rhombus is connected to the meandering structure having the scanning line 110 and the signal line 120, it has a roughly octagonal shape. In FIG. 6, both the scanning line 110 and the signal line 120 are straight lines, but outside of FIG. 6, they have a meandering structure as shown in FIG. 3.

In FIG. 6, an element 100 is arranged in an element region 101. The outer shape of the element 100 is approximately an octagon with the top of the diamond shape cut away. A signal line 120 and a scanning line 110 intersect below the element 100 with an insulating film interposed therebetween. However, FIG. 6 is a schematic diagram, and in an actual device, both the scanning line 110 and the video signal line 120 are connected to a transistor or the like that drives the element 100.

FIG. 7 is a sectional view taken along line DD in FIG. In FIG. 7, an inorganic insulating film 80 is formed on the base material 10. In FIG. The inorganic insulating film 80 blocks impurities and the like that enter from below into the element 100 and the like formed above it. In FIG. 7, the inorganic insulating film 80 is formed on the base material 10, but this is just an example, and the inorganic insulating film 80 may be formed in a layer close to the element 100 if necessary.

The inorganic insulating film 80 is formed of a silicon nitride film (SiN film), a silicon oxide film (SiO film), or a laminated film thereof. In some cases, an aluminum oxide film (AlO) may be used. Although the inorganic insulating film 80 has high rigidity, since it is formed only in the element region 101, its influence on the elasticity of the flexible electronic device 1 is small.

A first organic insulating film 20 is formed of polyimide, for example, covering the inorganic insulating film 80. A scanning line 110 extends in the lateral direction (x direction) on the first organic insulating film 20 . A second organic insulating film 30 is formed of, for example, polyimide, covering the scanning line 110 and the first organic insulating film 20. A signal line 120 extends on the second organic insulating film 30 in the y direction.

The element 100 is arranged to cover the signal line 120. FIG. 7 is a schematic diagram, and the connection structure between the element 100 and the scanning line 110, signal line 120, etc. is omitted. Actually, depending on what kind of element 100 is used, a thin film transistor (TFT) is arranged between the element 100 and the scanning line 110 or the signal line 120, and the TFT is connected to the scanning line control circuit 110. , the signal from the element 100 or the signal to the element 100 is often controlled by the signal line control circuit 125.

In FIG. 7, the wiring structure between the element 100 and the signal line 120 in FIG. 7 differs depending on what kind of element 100 is arranged. A plurality of organic or inorganic insulating films may be formed in the region where the element is formed. However, in FIG. 7 and the like, no insulating film is formed on the video signal line in order to make the flexible electronic device easy to expand and contract except in the region where the element 100 is formed.

The planar structure shown in FIG. 6 corresponds to the cross-sectional structure from the base material 10 to the element 100 in FIG. If this continues, the planar shape will be as shown in FIG. 3, which is unstable. Therefore, as explained in FIG. 4, the first buffer layer 40, the first protective layer 50, the second buffer layer 60, and the second protective layer 70 are formed, and the whole is put together into a flat plate shape to stabilize the shape. . Further, as explained in FIG. 4, the first buffer layer 40, the first protective layer 50, the second buffer layer 60, and the second protective layer 70 are composed of the base material 10, the first organic insulating film 20, and the second organic insulating film 20. Since a material having a smaller Young's modulus than the film 30 and the like is used, the structure is such that the stretchability of the flexible electronic device 1 is not impaired.

FIG. 8 is a plan view showing the shape of the base material 10 made of polyimide that constitutes the scanning line region and the element region. The element area 101 where the elements are arranged has a shape close to a rhombus, and the part of the scanning line area where the scanning lines are arranged near the element area is a straight line 111, but most of it has a meander structure 112. It has a structure that allows for flexible expansion and contraction.

FIG. 9 is a plan view showing problems when the structure of FIG. 8 is stretched in the direction of the white arrow. In this case, stress concentrates on the linear region 111 of the meandering structure 102 (hereinafter also simply referred to as the scanning line 110) having the rhombic element region 101 and the scanning line 110 and the joint portion B of the element region 101. Furthermore, since the element 100, the inorganic insulating film 80, etc. are present in the element region 101, the element region 101 has higher rigidity than other parts. Therefore, stress is more likely to be concentrated at the joint portion B between the diamond-shaped element region 101 and the scanning line linear region 111.

Even so, the resin such as polyimide that constitutes the base material 10 etc. has high strength, so it will not break, but the scanning line 110 formed of metal and extending on the base material 10 is broken at this part. It's easy to do. This situation is shown in FIG. FIG. 10 is a plan view showing that when the flexible electronic device 1 is pulled in the lateral direction (x direction), a break BB occurs in the scanning line 110 in a portion where stress is large. Embodiment 1 provides a configuration for preventing such disconnection of the scanning line 110. Although FIG. 10 shows an example in which the flexible electronic device 1 is stretched in the horizontal direction, a similar phenomenon occurs in the signal line 120 if the flexible electronic device is stretched in the vertical direction. The present invention is equally applicable to problems on the signal 120 side.

FIG. 11 is a plan view showing a schematic configuration of a first embodiment that solves the above problems. In FIG. 11, polyimide 102 forming the scanning line region and polyimide 101 forming the element region are separated. Therefore, the scanning line 110 is also divided at this portion. In FIG. 11, divided scanning lines 110 are connected by wire bonding 90. In FIG. In FIG. 11, 92 is a connection part, and 91 is a bonding wire. The connecting portion 92 may be configured to be easily connected by ball bonding or wedge bonding.

According to the present invention, when a flexible electronic device is stretched, stress is alleviated by substituting wire bonding for the portion where the most stress occurs on the wiring. 12 and 13 are cross-sectional views showing the principle of stress relief by wire bonding. In FIGS. 12 and 13, the cross-sectional structure is illustrated in a simplified manner. In FIG. 12, scanning lines are formed on base materials 101 and 102. The scanning line 110 of the base material 101 and the scanning line 110 of the base material 102 are connected by wire bonding 90.

In FIG. 12, the bonding wire 91 is connected in a bent state in the z direction. In FIG. 12, the distance 102 between the element region 101 and the meander region 102 is x1. FIG. 13 is a cross-sectional view when the flexible electronic device is stretched in the x direction and the distance 102 between the element region 101 and the meander region 102 is x2.

In this case, the stress caused by the stretching is borne by the organic material structure, for example, the first buffer layer 40, first protective layer 50, second buffer layer 60, second protective layer 70, etc. shown in FIG. do. On the other hand, in the wire bonding portion, only the bending of the bonding wire 91 in the z direction changes, and almost no stress occurs in wire bonding. Therefore, according to the configuration of FIG. 11, disconnection of the scanning line 110 as described in FIG. 10 can be avoided.

14 and subsequent figures are diagrams showing specific structures of FIGS. 11 to 13. By the way, the thickness of the bonding wire 91 in the wire bonding 90 is 15 μm to 30 μm. In FIG. 14 and subsequent figures, the thickness of the wire bonding wire is shown to be thinner than it actually is in order to make it easier to understand the relationship between the respective configurations.

FIG. 14 is a plan view of the vicinity of the wire bonding 90. In FIG. 14, the base material 10 is divided into an element region 101 and a scanning line region 111. Therefore, the scanning line 110 is also divided at this portion. In FIG. 14, the scanning line 110 on the element region 100 side and the scanning line 110 on the scanning line region 111 side are connected by wire bonding 90. Since the scanning line 110 is covered with the second organic insulating film, a through hole 95 for connection is formed in the second organic insulating film, and a pad 96 is further formed in this portion to enable wire bonding. The pad 96 is made of aluminum, copper, gold, or the like. Hereinafter, the connection portion 92 and bonding wire 91 will be collectively referred to as wire bonding 90.

FIG. 15 is a cross-sectional view in the x direction corresponding to FIG. 14. In FIG. 13, the base material 10, the first organic insulating film 20, the scanning line 110, and the second organic insulating film 30 are separated at the joint between the linear portion 111 of the element region 101 and the scanning line region 102. A through hole 95 is formed in the second organic insulating film 30 to connect the scanning lines 110 to each other by wire bonding 90, and a wire bonding pad 96 is formed in this portion.

In FIG. 15, the regions where the base material 10 and the like are divided are filled with a material constituting the first buffer layer 40. Further, the wire bonding 90 is covered with the first buffer layer 40 to relieve stress generated in the wire bonding 90. A first protective layer 50 is formed covering the first buffer layer 40 . A second buffer layer 60 is formed on the lower side of the base material 10, and a second protective layer 70 is formed on the lower side thereof. This configuration is the same as that described in FIG.

In FIG. 15, the regions where the base material 10, etc. are divided are filled with a material constituting the first buffer layer 40, and further, the base material 10, the first organic insulating film 20, the second organic insulating film 30, etc. It is sandwiched between the first buffer layer 40 and the second buffer layer 60. Therefore, even if it is stretched in the lateral direction (x direction), the strain at the wire bonding 90 portion will not become extremely large. Since the wire is about 15 μm to 30 μm, it can respond flexibly to stress.

16 to 24 are cross-sectional views of processes for realizing the configuration of FIG. 15. By the way, the manufacturing process is completely different depending on what kind of structure is used as the element 100 such as a sensor, how the element 100 is related to the scanning line 110 or the signal line 120, etc. The following description is an example of a process focusing on parts related to wire bonding 90. FIG. 16 is a cross-sectional view of a state in which a base material 10, a first organic insulating film 20, a scanning line 110, and a second organic insulating film 30 are formed in this order on a glass substrate 200. The glass 200 is necessary in the manufacturing process and is removed after the first protective layer 50 is formed.

In FIG. 16, for example, in order to form a base material 10 made of polyimide, a polyimide material is applied onto a glass substrate 200 and baked to imidize the material. When the first organic insulating film 20 is also formed of polyimide, the polyimide is applied covering the base material 10 and is baked and solidified. Thereafter, metal constituting the scanning line 110 is deposited, for example, by sputtering. The scanning line 110 is formed of, for example, TAT (Ti-Al-Ti) or MoW alloy. After patterning the scanning lines 110, the second organic insulating film 30 is formed of polyimide, for example.

FIG. 17 is a cross-sectional view showing a state in which the scanning line 110, the base material 10 supporting it, the first organic insulating film 20, and the second organic insulating film 30 are separated near the element region. Patterning may be wet etching or dry etching. FIG. 18 is a cross-sectional view showing a state in which a through hole 95 is formed in the second organic insulating film 30 and a scanning line 110 is partially exposed. FIG. 19 is a cross-sectional view showing a state in which a wire bonding pad 96 is formed in a through hole 95 portion. The material of the pad 96 that can be wire bonded is aluminum, copper, gold, or the like. In Example 1, Al is used.

FIG. 20 is a cross-sectional view showing a state in which two regions of the divided scanning line 110 are connected by wire bonding 90. The bonding wire 91 is made of aluminum, copper, gold, etc. and has a diameter of about 15 μm to 30 μm, for example. In the first embodiment, aluminum is used as the bonding wire 91. Bonding may be ball bonding or wedge bonding.

Thereafter, as shown in FIG. 21, the wire bonding 90, the second organic insulating film 30, the glass substrate 200, etc. are covered with the first buffer layer 40. Examples of the material for the first buffer layer 40 include acrylic, urethane, epoxy, and silicon. The first buffer layer 40 is also filled in regions where the scanning lines 110 are divided.

FIG. 22 is a cross-sectional view showing a state in which the first protective layer 50 is formed covering the first buffer layer 40. As shown in FIG. As for the material of the first protective layer 50, acrylic, urethane, epoxy, silicon, etc. are used similarly to the buffer layer. For example, when the required thickness cannot be secured with the first buffer layer 40 alone, there may be cases where the required thickness is secured with the first protective layer 50.

Thereafter, as shown in FIG. 23, the glass substrate 200 is peeled off. For example, a method can be used in which the interface between the glass substrate 200 and the base material 10 and the interface between the glass substrate 200 and the first buffer layer 40 are irradiated with a laser and the glass substrate 200 is peeled off. Thereafter, as shown in FIG. 24, a second buffer layer 60 is formed, followed by a second protective layer 70, thereby forming a flexible electronic device as shown in FIG. 15. The materials for the second buffer layer 60 and the second protective layer 70 are applied by turning the flexible electronic device upside down during the process. The second buffer layer 60 and the second protective layer 70 are made of any material such as acrylic, urethane, epoxy, silicon, etc., like the first buffer layer 40 and the first protective layer 50 .

The materials constituting the first buffer layer 40, the first protective layer 50, the second buffer layer 60, and the second protective layer 70 constitute the base material 10, the first organic insulating film 20, the second organic insulating film 30, etc. By using a material with a Young's modulus smaller than that of polyimide, a flexible electronic device with excellent stretchability can be manufactured. However, the first buffer layer 40, first protective layer 50, second buffer layer 60, and second protective layer 70 may be made of the same material as the base material 10, etc. It is determined by the ease of the manufacturing process of the flexible electronic device and the extent to which the flexible electronic device needs to be stretchable.

FIG. 25 is a plan view showing the second embodiment. The difference between FIG. 25 and FIG. 15 of Example 1 is that pads to be wire-bonded are not separately formed. For example, the scanning line 110 is composed of only base metal (titanium) and aluminum, and no cap layer is formed. Then, the surface of the scanning line 110 becomes aluminum, which can be used as a bonding pad. In FIG. 25, the width of the scanning line 110 is widened in the region where wire bonding 90 is performed, that is, in the portion corresponding to the through hole 95.

FIG. 26 is a cross-sectional view in the x direction including the wire bonding part 90 of FIG. 25. In FIG. 26, no special pad is formed in the through hole 95 of the second organic insulating film 30, and the wire bonding 90 is connected to the scanning line 110. The other configuration of FIG. 26 is the same as that of FIG. 15 of the first embodiment. In this manner, in the second embodiment, manufacturing costs can be reduced by not forming bonding pads for wire bonding.

In Examples 1 and 2, through holes 95 are formed in the second organic insulating film 30 to form bonding pads. In some cases, it may be more rational to form a notch 98 than to form a through hole in the second organic insulating film 30 having a width of approximately 30 μm. The cutout 98 is formed by etching the second organic insulating film 30 in the same way as through-hole formation.

FIG. 27 is a plan view of the third embodiment. 27 is different from FIG. 15 of Example 1 and FIG. 25 of Example 2 in that a notch 98 is formed in the second organic insulating film 30 in the bonding pad portion 97 instead of a through hole 95. It is. In order to form the bonding pad 97, the scan line 110 has a larger width at the notch 98.

FIG. 28 is a cross-sectional view in the x direction of FIG. 27. 28 differs from FIG. 26 of the second embodiment in that the bonding pad 97 is formed not in the through hole 95 but in the notch 98. A feature of the third embodiment is that the area in which the bonding pad 97 is formed can be made wider than in the first and second embodiments. Therefore, the degree of freedom in wire bonding work is increased, and connection reliability can be improved.

27 and 28, like the second embodiment, aluminum constituting the scanning line 110 is used as a bonding pad. However, as in the first embodiment, the bonding pads may be formed separately using aluminum, copper, gold, or the like. The manufacturing process of Example 3 differs from the manufacturing processes described in Example 1 and Example 2 only in that a notch 98 is formed in the second organic insulating film 30 instead of forming a through hole 95, so the explanation will be omitted. omitted.

In the above embodiment, in the vicinity of the element 100. Not only the scanning line 110 but also the base material 10, the first organic insulating film 20, and the second organic insulating film 30 are all removed. In such a configuration, when the flexible electronic device is expanded or contracted, a large stress may be applied to the divided portion.

The wire bonding 90 can flexibly respond to strain caused by this stress, but if the strain is too large, there is a risk that the wire bonding 90 will break. Embodiment 4 shown in FIGS. 29 and 30 has a configuration that takes measures against such problems.

FIG. 29 is a plan view of the fourth embodiment. In FIG. 29, as in Examples 1 to 3, the scanning line 110 is divided near the element region 101. However, in FIG. 29, the base material 10 and the first organic insulating film 20 are continuous without being separated.

FIG. 30 is a cross-sectional view in the x direction of FIG. 29. In FIG. 30, the scanning line 110 and the second organic insulating film 30 are separated, but the base material 10 and the first organic insulating film 20 are not separated and are continuous. Therefore, even when the flexible electronic device is stretched in the x direction, stress on the wire bonding 90 is alleviated due to the presence of the base material 10 and the first organic insulating film 20. Therefore, the resistance to expansion and contraction of the flexible electronic device can be further improved.

In addition, in FIGS. 29 and 30, only the base material 10 and the first organic insulating film 20 are made continuous, but if the second organic insulating film 30 is also made continuous, the wire bonding 90 when the flexible electronic device is stretched is It is possible to further alleviate stress. In this case, for example, the scanning line 110 on the first organic insulating film 20 is patterned, and then the second organic insulating film 30 is formed. Then, a through hole 95 is formed in the second organic insulating film 30. The subsequent process is the same as in Example 1.

The configurations of Examples 1 to 4 are examples in which wire bonding 90 is used in order to avoid the risk of disconnection of the scanning line 110 due to stress on the scanning line 110 when the flexible electronic device is stretched near the element 100. be. However, not all of the scanning lines 110 are disconnected in the target portion, and there is a risk of disconnection. On the other hand, if wire bonding 90 is used in this part, reliability will be significantly improved, but it is still not perfect. Therefore, the reliability of the connection can be further improved by adding connections by wire bonding 90 in a superimposed manner without dividing the scanning line 110.

FIG. 31 is a plan view of Example 5, and FIG. 32 is a cross-sectional view in the x direction of FIG. 31. The difference between FIGS. 31 and 32 from FIGS. 14 and 15 of Example 1 is that the scanning line 110, the base material 10, the first organic insulating film 20, and the second organic insulating film 30 are not separated in the x direction; This means that everything is continuous.

According to the configurations shown in FIGS. 31 and 32, when the flexible electronic device is expanded or contracted, if either the scanning line 110 or the wire bonding 90 survives, the device will operate, further improving reliability. . Moreover, in the part where the wire bonding 90 is formed, in addition to the scanning line 110, the base material 10, the first organic insulating film 20, and the second organic insulating film 30 are also present, so there is extreme stress concentration in this part. can also be avoided. Therefore, compared to Example 1 and the like, stress on the wire bonding when the flexible electronic device is expanded or contracted can be reduced.

Embodiments 1 to 5 take measures against the breakage of the scanning line when the flexible electronic device is expanded or contracted in the direction in which the scanning line extends (x direction). A similar phenomenon occurs with respect to the signal line when the flexible electronic device is expanded or contracted in the extending direction (y direction) of the signal line.

FIG. 33 is a plan view showing a state in which the signal line 120 is disconnected at a portion C where stress is concentrated when the flexible electronic device is stretched in the y direction. FIG. 34 is a plan view showing the configuration of Example 6, in which the problem in section C in FIG. 33 is addressed. 34 is similar to FIG. 14 of Embodiment 1, but the coordinate axes are y-direction, the scanning line 110 is changed to a signal line 120, and the second organic insulating film 30 has a through hole. There is no bonding pad 97.

FIG. 35 is a cross-sectional view of FIG. 34 in the lateral direction (y direction). The layer structure in FIG. 35 is as described in Example 1. Since the signal line 120 exists on the second organic insulating film 30, there is no need to form a through hole for the wire bonding 90, and the bonding pad 97 is formed directly on the signal line 120. There is.

Note that, as described with reference to FIG. 7, a plurality of insulating films are often formed between the signal line 120 and the element 100 depending on the structure of the element 100. However, in FIG. 35, such an insulating film is not formed on the signal line 120 in areas other than the region where the element 100 is formed, in order to easily maintain the expandability of the flexible electronic device.

FIG. 36 is a sectional view showing an intermediate step in forming the structure shown in FIG. Similarly to the scanning line 110, the signal line 120 also has a three-layer structure of Ti-Al-Ti. In FIG. 36, a bonding pad 97 made of aluminum, copper, gold, etc. is formed at the end of the signal line 120, but Ti is removed and Al is exposed at the end of the signal line 120. It may also be used as a bonding pad.

FIG. 37 is a cross-sectional view showing a state in which bonding pads 97 are connected by wire bonding 90. In FIG. 37, bonding pad 90 is planar, so bonding is easier. Thereafter, the process of forming the first buffer layer 40, first protective layer 50, second buffer layer 60, and second protective layer 70 is the same as that described in Example 1.

In the configuration of the flexible electronic device described above, there is no organic insulating film such as the second organic insulating film 30 on the signal line 120, and the signal line 120 is covered with the first buffer layer 40 made of an organic material. ing. When the signal line 120 is covered with an organic insulating film such as the second organic insulating film 30, a through hole may be formed in the organic insulating film covering the signal line 120, as in the first embodiment. In this case, configurations such as those in Examples 1 to 5 may be applied.

Generally, a stretchable flexible electronic device is assumed to be bent in four and eight directions, so both the configuration on the scanning line 110 side in Example 1 and the configuration on the signal line 120 side in Example 6 are used. It will be necessary to incorporate both.

The cross-sectional structure of the flexible electronic device described above is an example for explaining the present invention. The present invention can be applied not only to the cross-sectional structures explained in FIGS. 4, 5, and 7, but also to flexible electronic devices having other cross-sectional structures.

Furthermore, the arrangement of the scanning line drive circuit, signal line drive circuit, power supply circuit, etc. may be different from that in FIG. 1. Along with this, the layers in which the scanning lines and signal line drive circuits are arranged also differ from the configuration described above, but the present invention can be applied in the same way.

DESCRIPTION OF SYMBOLS 1... Flexible electronic device, 2... Element layer, 3... Upper protective layer, 4... Lower protective layer, 5... Active region, 6... Terminal region, 10... Base material, 20... First organic insulating film, 30... Second Organic insulating film, 40... Upper buffer layer, 50... Upper protective film, 60... Lower buffer layer, 70... Lower protective film, 80... Inorganic insulating film, 90... Wire bonding, 91... Bonding wire, 92... Bonding part, 95 ...Through hole, 96... Bonding pad, 97... Bonding pad, 98... Notch, 100... Element, 101... Element region of base material, 102... Meander structure region of base material, 110... Scanning line, 111... Straight line part, 112... Curved portion, 115... Scanning line drive circuit, 120... Signal line, 125... Signal line drive circuit, 130... Power supply circuit, 150... Flexible wiring board, 200... Glass substrate

Claims (16)

a plurality of elements arranged in a first direction at a first interval, arranged in a second direction at a second interval,
The plurality of elements are connected in a first direction by a first wiring and in a second direction by a second wiring, the electronic device comprising:
The element is formed in a first part of a first organic insulating film, the first wiring is formed in a second part of the first organic insulating film,
The first wiring has a straight first part near the element and a second curved part,
In the linear first portion, the first wiring is divided;
The electronic device, wherein the first wiring is connected at the divided portion by first wire bonding. 2. The electronic device according to claim 1, wherein the first organic insulating film is formed along the element and the first wiring. 2. The first portion and the second portion of the first organic insulating film are separated at a portion where the first wiring is separated. electronic equipment. 2. The electronic device according to claim 1, wherein the second curved portion of the first wiring has a meandering structure. 2. The electronic device according to claim 1, wherein an upper surface and a side surface of the first wiring and the first organic insulating film are covered with a second organic insulating film. 6. The electronic device according to claim 5, wherein the Young's modulus of the first organic insulating film is larger than the Young's modulus of the second organic insulating film. 2. The electronic device according to claim 1, wherein the electronic device has an operable elongation rate of 10% or more in the main surface direction. The electronic device according to claim 1, wherein the element includes a transistor or a diode. The electronic device according to claim 1, wherein the element is an optical sensor, a temperature sensor, a pressure sensor, a touch sensor, a light emitting element, or a light receiving element. The electronic device according to claim 1, wherein the element is an actuator. The second wiring is formed in a third portion of the first organic insulating film,
The second wiring has a linear third portion near the element and a curved fourth portion,
The second wiring is separated in the third linear portion,
2. The electronic device according to claim 1, wherein the second wiring is connected to the divided portion by second wire bonding. 12. The electronic device according to claim 11, wherein the first organic insulating film is formed along the second wiring. 12. The first portion and the third portion of the first organic insulating film are separated at a portion where the first wiring is separated. electronic equipment. 12. The electronic device according to claim 11, wherein the fourth curved portion of the second wiring has a meandering structure. 12. The electronic device according to claim 11, wherein an upper surface and a side surface of the second wiring and the first organic insulating film are covered with a second organic insulating film. a plurality of elements arranged in a first direction at a first interval, arranged in a second direction at a second interval,
The plurality of elements are connected in a first direction by a first wiring and in a second direction by a second wiring, the electronic device comprising:
The element is formed in a first part of a first organic insulating film, the first wiring is formed in a second part of the first organic insulating film,
The first wiring has a straight first part near the element and a second curved part,
An electronic device characterized in that wire bonding is formed in the first direction in the linear first portion of the first wiring.

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