TWI803242B - Electronic device and manufacturing method thereof - Google Patents

Abstract

The present disclosure provides an electronic device and a manufacturing method thereof. The electronic device includes a substrate, an electronic component, an underfill layer and a protective structure. The electronic component is disposed on the substrate. At least a portion of the underfill layer is disposed between the substrate and the electronic component. A thickness of the underfill layer is not greater than a height from a surface of the substrate to an upper surface of the electronic component. The protective structure is disposed on the substrate and adjacent to the underfill layer. The electronic device and the manufacturing method thereof of the present disclosure can effectively control the area of the underfill layer.

Description

Electronic device and manufacturing method thereof

The present invention relates to an electronic device and a manufacturing method thereof, and in particular to an electronic device capable of effectively controlling the area of an underfill adhesive layer and a manufacturing method thereof.

Generally speaking, after the electronic components are bonded to the substrate, an underfill process is performed to fill the underfill on the outside of the junction between the electronic components and the substrate by means of jetting process or dispensing process. The glue layer enters the gap between the electronic component and the substrate through the siphon phenomenon, so as to cover the pads and solder balls and fix the relative position between the electronic component and the substrate. However, the underfill adhesive layer flows freely on the substrate, so it is difficult to control its area, resulting in material waste, and even capacitance/inductance/electromagnetic interference.

The invention provides an electronic device and its manufacturing method, which can effectively control the area of the bottom filling adhesive layer.

The electronic device of the present invention includes a substrate, an electronic component, an underfill glue layer and a protection structure. The electronic components are arranged on the substrate. At least a part of the underfill glue layer is disposed between the substrate and the electronic component. The thickness of the underfill glue layer is not greater than the height from the surface of the substrate to the upper surface of the electronic component. The protection structure is disposed on the substrate and adjacent to the underfill adhesive layer.

The manufacturing method of the electronic device of the present invention includes the following steps. Substrate provided. Defines the restricted area of the substrate. Bonding electronic components on the substrate. An underfill adhesive layer is formed on the substrate.

Based on the above, in the embodiments of the present disclosure, the protection structure is disposed on the substrate and adjacent to the underfill layer, thereby limiting the range of the underfill layer, so that the electronic device of the present disclosure can effectively control the underfill layer. area, so that the amount and shape of the underfill layer can be consistent.

The present disclosure can be understood by referring to the following detailed description combined with the accompanying drawings. It should be noted that, in order to make the readers understand easily and for the simplicity of the drawings, several drawings in the present disclosure only depict a part of the electronic device. Also, certain elements in the drawings are not drawn to actual scale. In addition, the number and size of each component in the figure are only for illustration, and are not intended to limit the scope of the present disclosure.

Certain terms will be used throughout the specification and appended claims of this disclosure to refer to particular elements. Those skilled in the art should understand that electronic device manufacturers may refer to the same element by different names. This document does not intend to distinguish between those elements that have the same function but have different names.

In the description and claims below, words such as "comprising" and "comprising" are open-ended words, so they should be interpreted as meaning "including but not limited to...".

In addition, relative terms such as "below" or "bottom" and "upper" or "top" may be used in the embodiments to describe the relative relationship of one element to another element in the drawings. It will be appreciated that if the illustrated device is turned over so that it is upside down, elements described as being on the "lower" side will then become elements on the "upper" side.

In some embodiments of the present disclosure, terms such as “connected” and “interconnected” related to bonding and connection, unless otherwise specified, may mean that two structures are in direct contact, or may also mean that two structures are not directly (indirectly). ) contact with other structures interposed between the two structures. And the terms about joining and connecting may also include the situation that both structures are movable, or both structures are fixed. In addition, the term "coupled" includes the transfer of energy between two structures by means of direct or indirect electrical connection, or the transfer of energy between two separate structures by means of mutual induction.

It will be understood that when an element or film is referred to as being "on" or "connected to" another element or film, it can be directly on or directly connected to the other element or film To another element or layer, or there is an intervening element or layer between the two (indirect cases). In contrast, when an element is referred to as being "directly on" or "directly connected to" another element or film, there are no intervening elements or layers present.

The terms "about", "equal", "equal" or "same", "substantially" or "substantially" are generally interpreted as being within 20% of a given value or range, or as being within 20% of a given value or range Within 10%, 5%, 3%, 2%, 1%, or 0.5% of a value or range.

As used herein, the terms "film" and/or "layer" may refer to any continuous or discontinuous structures and materials (such as materials deposited by the methods disclosed herein). For example, films and/or layers may comprise two-dimensional materials, three-dimensional materials, nanoparticles, or even partial or complete molecular layers, or partial or complete atomic layers, or clusters of atoms and/or molecules. The film or layer may comprise a material or layer having pinholes, which may be at least partially continuous.

Although the terms first, second, third... may be used to describe various constituent elements, the constituent elements are not limited to this term. This term is only used to distinguish a single constituent element from other constituent elements in the specification. The same terms may not be used in the claims, but are replaced by first, second, third... in the order in which elements are declared in the claims. Therefore, in the following description, a first constituent element may be a second constituent element in the claims.

Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. It is understood that these terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning consistent with the background or context of the related art and the present disclosure, and not in an idealized or overly formal manner Interpretation, unless specifically defined herein.

It should be noted that in the following embodiments, without departing from the spirit of the present disclosure, technical features in several different embodiments may be replaced, reorganized, and mixed to complete other embodiments.

The electronic device of the present disclosure may include a display device, an antenna device, a sensing device, a light emitting device, and/or a splicing device, but is not limited thereto. Electronic devices may include bendable or flexible electronic devices. Electronic devices may include electronic components. Electronic components may include passive components and active components, such as capacitors, resistors, inductors, variable capacitors, filters, diodes, transistors, inductors, MEMS, liquid crystal chips ( liquid crystal chip), etc., but not limited thereto. The diodes may include light emitting diodes or photodiodes. The light emitting diodes may, for example, include organic light emitting diodes (organic light emitting diodes, OLEDs), submillimeter light emitting diodes (mini LEDs), micro light emitting diodes (micro LEDs), quantum dot light emitting diodes (quantum dot LED), fluorescence (fluorescence), phosphorescence (phosphor) or other suitable materials, or a combination of the above, but not limited thereto. The sensors may, for example, include capacitive sensors, optical sensors, electromagnetic sensors, fingerprint sensors (fingerprint sensor, FPS), touch sensors (touch sensor) , antenna (antenna), or stylus (pen sensor), etc., but not limited thereto. In the following, a display device is used as an electronic device to illustrate the content of the disclosure, but the disclosure is not limited thereto.

Reference will now be made in detail to the exemplary embodiments of the present disclosure, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers are used in the drawings and descriptions to refer to the same or like parts.

FIG. 1 is a schematic cross-sectional view of an electronic device according to an embodiment of the present disclosure. Please refer to FIG. 1 , in the present embodiment, an electronic device 100 a includes a substrate 110 , an electronic component 120 , an underfill layer 130 a and a protection structure 140 a. The electronic component 120 is disposed on the substrate 110 . At least a portion of the underfill layer 130 a is disposed between the substrate 110 and the electronic component 120 . The thickness T of the underfill adhesive layer 130 a is not greater than the height H from the surface S of the substrate 110 to the upper surface 121 of the electronic component 120 . The protection structure 140a is disposed on the substrate 110 and adjacent to the underfill layer 130a.

In detail, in this embodiment, the substrate 110 is, for example, a glass substrate, a glass fiber (FR4) substrate, a flexible plastic substrate, a film substrate, a flexible substrate or other suitable substrates, but is not limited thereto. Thin film transistors or other driving circuits can be arranged on the substrate. The substrate 110 includes a plurality of first pads 112 separated from each other, wherein the first pads 112 may be disposed on the surface S of the substrate 110 , but not limited thereto. In another embodiment, the surface of the substrate has a recessed portion, and the first pad 112 may also be disposed in the recessed portion, which still belongs to the protection scope of the present disclosure.

The electronic component 120 is, for example, a light-emitting diode chip (LED die), which can be made of silicon (Si), gallium arsenide (GaAs), gallium nitride (GaN), silicon carbide (SiC), sapphire (Sapphire) or glass A wafer made from a substrate, but not limited thereto. In another embodiment, the electronic component 120 can also be a semiconductor package component, such as a Ball Grid Array (BGA) package component, a chip size package (Chip Size Package, CSP) component, a flip chip or a 2.5 Dimensional/3-dimensional (2.5D/3D) semiconductor package components, but not limited thereto. In another embodiment, the electronic component 120 can also be any kind of chip, such as integrated circuits (ICs), transistors (transistors), silicon controlled rectifiers, valves (valves), thin film transistors (Thin Film Transistors), capacitors, Inductors, variable capacitors, filters, resistors, diodes, MEMS, liquid crystal chips, etc., but not limited thereto. The electronic component 120 includes a plurality of second pads 122 separated from each other, wherein the first pad 112 and the second pad 122 are structurally and electrically connected together through a plurality of solder balls 150 . That is to say, the electronic component 120 of this embodiment is bonded on the substrate 110 in a flip-chip manner, for example.

As shown in FIG. 1 , the underfill adhesive layer 130 a is disposed between the substrate 110 and the electronic component 120 , and covers the first pad 112 , the second pad 122 and the solder ball 150 . The underfill adhesive layer 130 a can be used to increase the adhesion between the electronic component 120 and the substrate 110 , and can fix the relative positions of the first pad 112 , the solder ball 150 and the second pad 122 . In one embodiment, when the electronic device 100a is, for example, an antenna device or a sensing device, when the thickness T of the underfill adhesive layer 130a is not greater than the height H from the surface S of the substrate 110 to the upper surface 121 of the electronic component 120 , it can allow the high-frequency signal to pass and reduce the loss of the high-frequency signal. In another non-illustrated embodiment, in order to further reduce signal loss, the thickness of the underfill glue layer under the electronic component may be smaller than the height from the surface of the substrate to the lower surface of the electronic component. In another unillustrated embodiment, the underfill adhesive layer can also completely cover the electronic components. In the case of electronic components such as light-emitting diodes, the electronic device can have a better light pattern and light-gathering effect. .

In addition, the arrangement of the protective structure 140a in this embodiment can define a restricted area A on the substrate 110, where the protective structure 140a is, for example, a closed structure, such as a continuous mountain-shaped dam or a continuous retaining wall ( wall) can surround the underfill adhesive layer 130a to limit the area of the underfill adhesive layer 130a. In other words, the underfill layer 130a is located in the restricted area A in a restricted manner. In one embodiment, the material of the protection structure 140a may be, for example, an organic material, but is not limited thereto. The top view shape of the protection structure 140 a may be, for example, a hollow rectangle, and the thickness of the protection structure 140 a may be, for example, 1 micrometer (μm) to 100 μm, but is not limited thereto.

In manufacturing, please refer to FIG. 1 again. Firstly, a substrate 110 is provided, wherein the substrate 110 includes first pads 112 . The material of the first pad 112 may be electroless nickel gold (abbreviated as ENIG: Electroless nickel immersion gold) or other conductive materials. Next, a protection structure 140 a is formed on the substrate 110 to define a restricted area A of the substrate 110 . Next, the electronic component 120 is bonded on the substrate 110, wherein the electronic component 120 includes a second pad 122, and the material of the second pad 122 can be electroless nickel gold (abbreviated as ENIG: Electroless nickel immersion gold) or other conductive materials . The first pad 112 and the second pad 122 are structurally and electrically connected together through a plurality of solder balls 150 . It should be noted that the present disclosure does not limit the sequence of forming the protection structure 140 a on the substrate 110 and bonding the electronic device 120 on the substrate 110 . That is to say, the protection structure 140 a can be formed on the substrate 110 first, and then the electronic component 120 is bonded on the substrate 110 ; or, the electronic component 120 is bonded on the substrate 110 first, and then the protection structure 140 a is formed on the substrate 110 . Finally, an underfill adhesive layer 130 a is formed on the substrate 110 , wherein the underfill adhesive layer 130 a is disposed between the substrate 110 and the electronic component 120 and covers the first pad 112 , the second pad 122 and the solder ball 150 . So far, the fabrication of the electronic device 100a is completed.

In short, the protective structure 140a of this embodiment can limit the area of the underfill adhesive layer 130a, so that the amount and shape of the underfill adhesive layer 130a are consistent. Considering the application of the electronic device 100a in high-frequency transmission, the material loss of the high-frequency signal in the electronic device 100a needs to be consistent. That is to say, in this embodiment, the amount of the underfill adhesive layer 130a is adjusted/limited by setting the protective structure 140a, so that the electronic device 100a of this embodiment can effectively control the area of the underfill adhesive layer 130a.

It should be noted here that the following embodiments use the component numbers and partial content of the previous embodiments, wherein the same numbers are used to denote the same or similar components, and descriptions of the same technical content are omitted. For the description of omitted parts, reference may be made to the foregoing embodiments, and the following embodiments will not be repeated.

FIG. 2A is a schematic top view of an electronic device according to an embodiment of the present disclosure. Please refer to FIG. 1 and FIG. 2A at the same time. The electronic device 100b is similar to the electronic device 100a in FIG. 1 . The difference between them is that in this embodiment, the protection structure 140b may be a non-enclosed structure in consideration of uniformity. In detail, the protection structure 140b of this embodiment has a plurality of openings 145b (two openings 145b are schematically shown), and includes a plurality of retaining wall patterns 142b (two retaining wall patterns 142b are schematically shown) separated from each other. . The size of the retaining wall pattern 142b may be the same, and may be a mirror image structure, but not limited thereto. The opening 145b is located between the retaining wall patterns 142b, wherein the shape of the opening 145b is, for example, a rectangle, and part of the underfill adhesive layer 130b extends into the opening 145b. The design of the opening 145b not only accommodates overflowing glue, but also has the function of venting, which can remove the air existing in the underfill glue layer 130b.

FIG. 2B is a schematic top view of an electronic device according to another embodiment of the present disclosure. Please refer to FIG. 2A and FIG. 2B at the same time. The electronic device 100c is similar to the electronic device 100b in FIG. Wall pattern 142c. The size of the retaining wall patterns 142c can be the same, and the four retaining wall patterns 142c are arranged in a swastika shape, but not limited thereto. The opening 145c is located between the retaining wall patterns 142c, wherein the diameter of the opening 145c gradually increases from the direction adjacent to the underfill layer 130b to the direction away from the underfill layer 130b, such as a trapezoidal shape, and part of the underfill layer 130b extends to the opening. Within 145c. The design of the opening 145c not only accommodates overflowing glue, but also has the function of venting, which can remove the air existing in the underfill glue layer 130b.

In another unillustrated embodiment, considering the wetting conditions, the multiple retaining wall patterns of the protective structure may also have different sizes, or the shapes of these retaining wall patterns may also be different and asymmetrical , which still belongs to the scope of protection intended by this disclosure.

FIG. 3 is a schematic top view of an electronic device according to another embodiment of the present disclosure. Please refer to FIG. 1 and FIG. 3 at the same time. The electronic device 100d is similar to the electronic device 100a in FIG. , disposed on the substrate 110 and between the protection structure 140d and the substrate 110 to prevent the underfill adhesive layer 130d from overflowing. In one embodiment, the orthographic projection of the protection structure 140d on the substrate 110 completely overlaps the orthographic projection of the metal layer 160 on the substrate 110, wherein the orthographic projection of the metal layer 160 on the substrate 110 is smaller than that of the protection structure 140d on the substrate 110 The orthographic projection of , but not limited to.

4A to 4C are schematic cross-sectional views of a method for manufacturing an electronic device according to an embodiment of the present disclosure. First, please refer to FIG. 4A , a substrate 110 is provided, wherein the substrate 110 includes first pads 112 . Next, the electronic component 120 is bonded on the substrate 110 , wherein the electronic component 120 includes the second pad 122 , and the first pad 112 and the second pad 122 are structurally and electrically connected together through the solder ball 150 . Next, a steel plate P is disposed on a part of the surface S of the substrate 110 , wherein the steel plate P surrounds the electronic component 120 . Next, the electronic components 120 and the substrate 110 exposed outside the steel plate P are irradiated with the energy beam L. Referring to FIG. Here, the energy beam L is, for example, extreme ultraviolet light (Extreme Ultra Violet, EUV) or plasma (Plasma), which can effectively reduce the contact angle (contact angle) of the substrate 110, so as to increase the subsequent underfill adhesive layer 130a (please refer to FIG. 4c) Wettability. After that, referring to FIG. 4B , the steel plate P is removed to define a restricted area A on the substrate 110 . That is to say, the step of defining the restricted area A of the substrate 110 in this embodiment is to treat the surface S of the substrate 110 with the energy beam L to modify the surface of a partial area of the substrate 110 (ie, the restricted area A). Finally, please refer to FIG. 4B and FIG. 4C at the same time, forming the underfill adhesive layer 130a on the substrate 110, wherein the underfill adhesive layer 130a can easily flow to the restricted area A through the siphon phenomenon to cover the first pad 112, the second Two bonding pads 122 and solder balls 150 , and the underfill adhesive layer 130 a will not flow to the area without surface modification (ie, the area outside the restricted area A). So far, the fabrication of the electronic device 100e has been completed.

5A to 5B are schematic cross-sectional views of partial steps of a method for manufacturing an electronic device according to another embodiment of the present disclosure. First, please refer to FIG. 5A , a substrate 110f is provided, wherein the substrate 110f includes first pads 112 . Next, a part of the substrate 110f is covered with a photoresist. Next, the substrate 110f is subjected to surface treatment by means of plasma, sandblasting or etching, so as to form a rough surface structure R in the region of the substrate 110f not covered with photoresist, thereby defining a restricted region A of the substrate 110f . Afterwards, the photoresist is removed, and the electronic component 120 is bonded on the substrate 110f, wherein the electronic component 120 includes the second pad 122, and the first pad 112 and the second pad 122 are structurally and electrically connected through the solder ball 150 connected sexually. Finally, referring to FIG. 5A and FIG. 5B at the same time, an underfill adhesive layer 130a is formed on the substrate 110f, wherein the underfill adhesive layer 130a can easily flow to the restricted area A through the siphon phenomenon to cover the first pad 112, the second The two pads 122 and the solder balls 150 are solidified, and the underfill adhesive layer 130 a will not flow onto the surface roughness R. So far, the fabrication of the electronic device 100f has been completed.

Since the underfill adhesive layer 130a will not be wetted when the roughness is high, the flow range of the underfill adhesive layer 130a can be limited by roughening the surface in the area where the underfill adhesive layer 130a is not needed, so as to control the underfill adhesive layer 130a. Fill the area of the glue layer 130a.

In another unillustrated embodiment, the rough surface structure R may also be replaced by a plurality of microstructures separated from each other. Specifically, first, a substrate is provided. Then, a part of the substrate is covered with photoresist, and a microstructure is fabricated through steps such as a photolithography process, so as to define a restricted area of the substrate. After that, the electronic components are bonded on the substrate. Finally, an underfill adhesive layer is formed on the substrate, wherein the underfill adhesive layer can easily flow to the restricted area through the siphon phenomenon to be cured, and the underfill adhesive layer will not flow onto the microstructure. So far, the fabrication of the electronic device has been completed.

6A to 6C are schematic cross-sectional views of a method of manufacturing an electronic device according to another embodiment of the present disclosure. First, please refer to FIG. 6A , a substrate 110 is provided, wherein the substrate 110 includes first pads 112 . Next, the fluorine-containing substance is coated on the substrate 110 by screen printing. Next, the fluorine-containing substance is dried to dehydrate the surface S of the substrate 110 and the fluorine-containing substance to generate Si-O bonds, thereby forming a hydrophobic protective structure 140g, and defining the restricted area A of the substrate 110 with the protective structure 140g. Next, please refer to FIG. 6B , bonding the electronic component 120 on the substrate 110, wherein the electronic component 120 includes the second pad 122, and the first pad 112 and the second pad 122 are structurally and electrically connected through the solder ball 150 together. Finally, please refer to FIG. 6B and FIG. 6C at the same time, forming the underfill adhesive layer 130a on the substrate 110, wherein the underfill adhesive layer 130a can easily flow to the restricted area A through the siphon phenomenon, so as to cover the first pad 112, the second pad 112 The two pads 122 and the solder balls 150 are cured, and the underfill adhesive layer 130a does not flow onto the protection structure 140g. So far, the fabrication of the electronic device 100g has been completed.

Since the surface S of the substrate 110 is coated with a fluorine-containing substance, a hydrophobic protective structure 140g is formed, so that the underfill adhesive layer 130a will not be wetted by the protective structure 140g, thereby limiting the flow range of the underfill adhesive layer 130a , so as to control the area of the underfill layer 130a.

In another unillustrated embodiment, the fluorine-containing substance can also be replaced by a polymer (pollymer), such as a fluorocarbon polymer (Fluorocarbon polymer). Specifically, first, a substrate is provided. Next, using Octafluorocyclobutane (C4F8) as the reaction gas, a fluorocarbon polymer film is formed on the substrate by inductively coupled plasma chemical vapor deposition (ICP-CVD) at room temperature, in which the fluorocarbon polymer Thin film covers the entire surface of the substrate. Then, the fluorocarbon polymer film is patterned by photolithography to form a hydrophobic protection structure and define the restricted area of the substrate. That is, in addition to fluorocarbon chains that lower the surface energy, silanes can also be used to form hydrophobic surfaces. After that, the electronic components are bonded on the substrate. Finally, an underfill adhesive layer is formed on the substrate, wherein the underfill adhesive layer can easily flow into the restricted area through the siphon phenomenon to be cured, and the underfill adhesive layer cannot flow onto the protection structure. So far, the fabrication of the electronic device has been completed.

To sum up, in the embodiments of the present disclosure, the protection structure is disposed on the substrate and adjacent to the underfill adhesive layer, thereby limiting the scope of the underfill adhesive layer, so that the electronic device of the present disclosure can effectively control the underfill. The area of the adhesive layer, and thus the amount and shape of the underfill adhesive layer can be consistent.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, rather than limiting them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: It is still possible to modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the technical solutions of the various embodiments of the present invention. scope.

100a, 100b, 100c, 100d, 100e, 100f, 100g: electronic device 110, 110f: substrate 112: First pad 120: Electronic components 121: upper surface 122: Second pad 130a, 130b, 130d: underfill glue layer 140a, 140b, 140c, 140d, 140g: protective structure 142b, 142c: retaining wall pattern 145b, 145c: opening 150: solder ball 160: metal layer A: Restricted area H: height L: energy beam P: steel plate R: rough surface structure S: surface T: Thickness

FIG. 1 is a schematic cross-sectional view of an electronic device according to an embodiment of the present disclosure. FIG. 2A is a schematic top view of an electronic device according to an embodiment of the present disclosure. FIG. 2B is a schematic top view of an electronic device according to another embodiment of the present disclosure. FIG. 3 is a schematic top view of an electronic device according to another embodiment of the present disclosure. 4A to 4C are schematic cross-sectional views of a method for manufacturing an electronic device according to an embodiment of the present disclosure. 5A to 5B are schematic cross-sectional views of partial steps of a method for manufacturing an electronic device according to another embodiment of the present disclosure. 6A to 6C are schematic cross-sectional views of a method of manufacturing an electronic device according to another embodiment of the present disclosure.

100a: electronic device

110: Substrate

112: First pad

120: Electronic components

121: upper surface

122: Second pad

130a: Underfill rubber layer

140a: Protective structure

150: solder ball

H: height

S: surface

T: Thickness

Claims (6)

An electronic device, comprising: a substrate; an electronic component disposed on the substrate; an underfill adhesive layer, at least a part of the underfill adhesive layer is disposed between the substrate and the electronic component, wherein the thickness of the underfill adhesive layer is not greater than a height greater than the surface of the substrate to the upper surface of the electronic component; a protection structure disposed on the substrate and adjacent to the underfill layer; and a metal layer disposed on the substrate between the protection structure and the substrate , wherein the orthographic projection of the metal layer on the substrate is smaller than the orthographic projection of the protection structure on the substrate. The electronic device as claimed in claim 1, wherein the protection structure surrounds the underfill adhesive layer. The electronic device as claimed in claim 1, wherein the protection structure comprises a plurality of retaining wall patterns. The electronic device as claimed in claim 1, wherein the protective structure includes a fluorine-containing substance. The electronic device of claim 1, wherein the protective structure comprises a polymer. The electronic device of claim 5, wherein the protective structure comprises fluorocarbon polymer.

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