A flexible electronic device, a method of manufacturing the same, and a flexible electronic apparatus

Abstract

The application provides a flexible electronic device and a preparation method thereof and a flexible electronic device. The method comprises the following steps: providing a substrate; patterning the surface of the substrate to form a buried groove and a flexible groove; the number of the buried grooves is multiple, and the buried grooves are respectively located on both sides of the flexible groove; pasting a chip into the buried groove, and a gap exists between the chip and the side wall of the buried groove; using a dry film lamination process to press a photoetching material into the flexible groove and the gap, and forming a photoetching film layer covering the surface of the substrate; patterning the photoetching film layer and metal wiring to form a redistribution layer of the chip pasted into the buried groove; removing the excess substrate material on both sides of the flexible structure formed in the flexible groove; and performing back thinning on the substrate until the flexible structure is exposed. In the application, the flexible structure is prepared in the substrate, the substrate is flexible, the flexibility of the electronic device is realized, and the flexible demand of the electronic device with high performance is met.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of flexible electronic technology, in particular to a flexible electronic device and a preparation method thereof, and a flexible electronic device. BACKGROUND

[0002] The advent of the information age has brought new intelligent requirements such as wearable, implantable and human-computer interaction for information terminals, which brings new challenges to traditional rigid electronic devices, and it is urgent to explore the implementation scheme of flexible electronic information system. Flexible electronic technology integrates knowledge of microelectronics, materials science, mechanics, bionics and other interdisciplinary knowledge. The flexible electronic system prepared by the flexible electronic technology can effectively work under multiple deformation modes such as bending, folding, stretching and twisting, and has wide demand and application prospect in wearable / implantable devices, aerospace, health care, intelligent networking and future smart society. The flexible electronic technology emerging as the times require has become a research hotspot in the field of electronic technology worldwide, and is considered as an important direction for the future development of electronic information systems.

[0003] At present, there are two technical routes for the preparation process of flexible electronic systems: one is to use intrinsically flexible organic polymer, organic semiconductor and other organic materials to prepare flexible electronic devices by printing and surface modification technology; the other is to transfer ultra-thin inorganic materials to flexible or elastic substrates to realize the flexibility of inorganic semiconductor chips.

[0004] The first technical route is based on the development of organic semiconductor materials. Since the organic semiconductor itself has excellent bending and stretching characteristics, the flexible process of this method is simple, and it is easy to realize printing, patterning, thin film forming and forming a flexible electronic system. For the second route, the core idea is to use ultra-thin silicon materials (silicon nanometer film, silicon nanometer strip and silicon nanometer line) to realize flexible electronic devices based on inorganic materials with the assistance of elastomers.

[0005] The flexible electronic devices prepared directly using organic materials have good flexibility and can be prepared on a certain scale by synthesis and other methods. However, the low mobility of the known organic semiconductors is still an important factor limiting their performance. For example, the elastic organic semiconductor material studied by the existing team can maintain a carrier mobility of 1.5 cm 2 / V·s when stretched from the free state to twice the original length, but it is still much smaller than the carrier mobility of silicon (102 -103cm 2Inorganic semiconductor materials represented by silicon not only have higher mobility, but also have a mature set of large-scale manufacturing processes. By using appropriate methods to make silicon-based structures flexible, higher-performance flexible electronic devices can be obtained, and large-scale manufacturing is easy to achieve, thereby facilitating industrial transformation. However, the flexible electronic devices manufactured by the existing process have low reliability and are incompatible with the existing large-scale manufacturing process, which cannot meet the flexible needs of higher-performance electronic devices. SUMMARY

[0006] The purpose of the present application is to provide a flexible electronic device and a preparation method thereof, and a flexible electronic device to meet the flexible needs of higher-performance electronic devices.

[0007] In a first aspect, the present application provides a preparation method of a flexible electronic device, comprising:

[0008] providing a substrate;

[0009] performing patterning on the surface of the substrate to form embedded grooves and flexible grooves; the number of embedded grooves is multiple, and each embedded groove is located on the two sides of a flexible groove;

[0010] attaching a chip into the embedded groove, and a gap exists between the chip and the side wall of the embedded groove;

[0011] using a dry film lamination process to press a photoetching material into the flexible groove and the gap, and form a photoetching film layer covering the surface of the substrate;

[0012] performing patterning and metal wiring on the photoetching film layer to form a redistribution layer of the chip attached into the embedded groove;

[0013] removing the excess substrate material on both sides of the flexible structure formed in the flexible groove;

[0014] back-thinning the substrate until the flexible structure is exposed.

[0015] In some embodiments of the present application, the flexible groove is a meander-shaped flexible groove, a paper-cut structure flexible groove, or a paper-folding structure flexible groove.

[0016] In some embodiments of the present application, the depth of the embedded groove and the flexible groove is the same or different.

[0017] In some embodiments of the present application, the step of attaching the chip into the embedded groove comprises:

[0018] attaching the chip with a die-bonding adhesive film attached to the back thereof into the embedded groove by a flip-chip bonder or a sub-micron chip bonder.

[0019] In some embodiments of the present application, the photoetching material is a dry film material or a polyimide material.

[0020] In some embodiments of the present application, the metal wiring is a Ti / Al, Ti / Cu or Ti / Au alloy.

[0021] In some embodiments of the present application, the removing of the excess substrate material on both sides of the flexible structure formed in the flexible groove comprises:

[0022] The excess substrate material on both sides of the flexible structure formed in the flexible groove is removed by dry etching.

[0023] In some embodiments of the present application, the substrate is a silicon substrate.

[0024] In a second aspect, the present application provides a flexible electronic device, which is prepared by the preparation method of the flexible electronic device of the first aspect.

[0025] In a third aspect, the present application provides a flexible electronic device, which comprises the flexible electronic device of the second aspect.

[0026] Compared with the prior art, the preparation method of the flexible electronic device provided by the present application comprises the following steps: providing a substrate; patterning the surface of the substrate to form a buried groove and a flexible groove; the number of the buried grooves is multiple, and each of the buried grooves is located on both sides of the flexible groove; pasting a chip into the buried groove, and a gap exists between the chip and the side wall of the buried groove; using a dry film lamination process to press a photoetching material into the flexible groove and the gap, and to form a photoetching film layer covering the surface of the substrate; patterning the photoetching film layer and metal wiring to form a redistribution layer of the chip pasted into the buried groove; removing the excess substrate material on both sides of the flexible structure formed in the flexible groove; and back-thinning the substrate until the flexible structure is exposed. In the present application, the flexible structure is prepared in the substrate, so that the substrate is flexible, thereby realizing the flexibility of the electronic device, and a flexible electronic device with higher performance can be obtained. Compared with the flexible electronic device prepared by the prior art, the present application has high reliability and is compatible with the existing large-scale manufacturing process, thereby meeting the flexible demand of the electronic device with higher performance. BRIEF DESCRIPTION OF DRAWINGS

[0027] Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The accompanying drawings are included to provide a better understanding of the preferred embodiments, and are not to be considered as limitations. Moreover, the same reference numerals are used throughout the accompanying drawings to represent same or similar components. In the drawings:

[0028] Figure 1 A flow chart of a method for manufacturing a flexible electronic device is shown;

[0029] Figures 2A to 2H A schematic diagram of a forming process of a flexible electronic device is shown;

[0030] Figure 3 A schematic diagram of a flexible structure made by using a meandering flexible slot is shown;

[0031] Figure 4 A top view of a flexible electronic device is shown; Figures 2A to 2H A top view of a flexible electronic device is shown;

[0032] Figure 5 A top view of a flexible structure made by a paper-cut structure flexible slot is shown.

[0033] Reference signs:

[0034] Substrate 10; embedded slot 110; flexible slot 120; chip 111; gap 112; die-bonding adhesive film 113; photoetching film layer 20; flexible structure 210; rewiring layer 30. DETAILED DESCRIPTION

[0035] Exemplary embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure can be embodied in various forms without being limited by the embodiments set forth herein. Rather, these embodiments are provided so that the present disclosure will be thorough and complete, and will fully convey the scope of the present disclosure to those skilled in the art.

[0036] It should be noted that the technical terms or scientific terms used in the present application should be understood as their general meanings understood by those skilled in the art, unless otherwise specified.

[0037] In addition, the terms "first" and "second" and the like are used to distinguish different objects, rather than to describe a particular order. Furthermore, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device including a series of steps or units is not limited to the listed steps or units, but can optionally include other steps or units not listed or can optionally include other steps or units inherent to the process, method, product or device.

[0038] To further illustrate the scheme of the embodiments of the present application, the following will be described with reference to the accompanying drawings. It can be understood that in the following embodiments, the same or corresponding contents can be referred to each other, and for the sake of simplicity of description, the subsequent will not be described repeatedly.

[0039] Many domestic and foreign mobile phone manufacturers have launched flexible commercial products such as folding screen mobile phones and tablets. The bending mainly depends on the flexibility of display materials. The integrated circuit (IC) chip and sensor (especially high-performance sensor) are still rigid. Therefore, strictly speaking, the existing flexible electronic products are "flexible in shape and not flexible in core": only the outer part is flexible (the base uses flexible materials), and the inner part is not flexible (the core IC and sensor chip itself has flexibility). To obtain truly flexible high-performance flexible electronic products with flexible shape and core, it is necessary to develop flexible processing methods for electronic devices that are compatible with integrated circuit technology, can stably ensure electrical performance, and can be mass-produced, as well as flexible hybrid integration methods for multiple heterogeneous and heterogeneous chips, so that electronic devices can be fully flexible from the inside out, greatly reducing the weight and volume of smart hardware by reducing the application of packaging structures and materials, improving human-machine interaction by improving the ability to attach to the human body, and enabling the unprecedented deep integration of smart devices and the physical world.

[0040] Current research in the field of flexible electronics mainly focuses on flexible display screens, flexible super capacitors, and flexible functional materials. However, there is still a gap in high-performance flexible electronic systems such as flexible touch force sensor arrays and flexible memory chips. For example, touch force sensors are considered a core component of industrial robots. The sensing materials widely used in existing flexible touch force sensors are mainly carbon-based sensitive materials (carbon nanotubes, graphene, etc.), conductive polymer materials, and inorganic piezoelectric materials. Due to the limitations of material properties and processing methods, flexible touch force sensors made from the above materials have problems such as poor batch consistency, difficulty in arraying, large unit area, large temperature drift, poor linearity, poor stability, and inability to mass-produce. In addition, the preparation of flexible memory chips usually uses SOI technology or bulk silicon thinning technology to achieve chip flexibility, but the bending radius cannot be further reduced. Therefore, it is urgent to develop flexible processing methods for high-reliability and high-performance flexible electronic devices that are compatible with integrated circuit technology and can be mass-produced, as well as flexible hybrid integration methods for multiple heterogeneous and heterogeneous chips, to realize high-performance flexible electronic systems (including silicon-based MEMS sensors and silicon-based IC chips).

[0041] The ultra-thin silicon structure obtained by the existing method has low reliability, complex interconnection process between the flexible substrate, and is not compatible with the existing mass production process, which cannot meet the flexible requirements of high-performance silicon-based MEMS sensors / actuators with thickness requirements. Other technical solutions, such as flexible electronic devices prepared based on Parylene MEMS technology, have the following defects due to the physical and chemical properties of Parylene itself:

[0042] 1. High cost: The material and coating process of parylene are relatively expensive, making it cost-prohibitive for large-scale applications.

[0043] 2. High surface cleanliness requirements: Parylene coatings require a very high level of cleanliness on the substrate surface. Any minor contaminants can affect the adhesion and overall performance of the coating.

[0044] 3. Limited mechanical strength: Parylene has relatively low mechanical strength and wear resistance, which may not be suitable for applications that require high mechanical strength and wear resistance.

[0045] 4. Difficult to repair: Once the parylene coating is damaged or defective, it is difficult to repair, and usually requires re-coating.

[0046] 5. Complex process: The coating process of parylene needs to be carried out in a vacuum environment, and the process parameters need to be precisely controlled, which increases the complexity of the process and the requirements for equipment.

[0047] 6. Limited high-temperature resistance: Parylene has poor stability at high temperatures. Although it has good performance at room temperature, its mechanical properties and chemical stability may decrease significantly when the temperature exceeds 100°C, which limits its use in high-temperature applications.

[0048] 7. Adhesion problems: Parylene has relatively poor adhesion on some substrates. Although proper surface treatment (such as plasma treatment) can improve its adhesion, adhesion problems still exist on some special materials or complex surfaces. This may cause the coating to peel off or peel off during long-term use, affecting the reliability of the package.

[0049] Therefore, the present application provides a method for preparing a flexible electronic device, which is described below in conjunction with the accompanying drawings.

[0050] Figure 1 A flowchart of the method for preparing a flexible electronic device provided by the present application is shown; Figures 2A to 2H A schematic diagram of the formation process of the flexible electronic device provided by the present application is shown.

[0051] As Figure 1 shown, the method for preparing a flexible electronic device provided by the present application includes the following steps:

[0052] S101, providing a substrate 10;

[0053] Figure 2AThe cross-sectional view of the substrate 10 is shown. The surface of the substrate 10 can be circular or square, which is not limited in the present application. Specifically, the substrate 10 can be a silicon substrate, and other inorganic semiconductor material substrates can also be used. Silicon-based inorganic semiconductor materials have higher mobility and a mature scale manufacturing process. By using appropriate methods to realize the flexibility of silicon-based structures, higher performance flexible electronic devices can be obtained, and scale manufacturing is easy to realize, thereby facilitating industrial transformation.

[0054] S102, the surface of the substrate 10 is patterned to form a buried groove 110 and a flexible groove 120; the number of the buried groove 110 is multiple, and is located on both sides of the flexible groove 120;

[0055] The buried groove 110 is used for the embedding of electronic device chips. The flexible groove 120 is used to form a flexible structure to realize the flexibility of electronic devices and realize bendability.

[0056] Figure 2B The cross-sectional view after forming the buried groove 110 and the flexible groove 120 in the substrate 10 is shown. The depth of the buried groove 110 and the flexible groove 120 can be the same or different, and the specific value of the depth can be set according to actual needs.

[0057] Specifically, the flexible groove 120 can be a meandering flexible groove, a Kirigami structure flexible groove, or an Origami structure flexible groove.

[0058] In the present application, the substrate is etched with a chip embedding groove and a flexible groove. The flexible groove can be a meandering flexible groove, or a flexible groove designed with a structure similar to Kirigami, Origami, etc.

[0059] S103, the chip 111 is attached to the buried groove 110, and a gap 112 exists between the chip 111 and the side wall of the buried groove 110;

[0060] Figure 2C The cross-sectional view after the chip 111 is attached to the buried groove 110 is shown.

[0061] Specifically, the chip 111 with a die bonding adhesive film 113 attached to the back can be attached to the buried groove 110 by a flip chip bonder or a sub-micron chip mounter.

[0062] Die Attach Film (DAF) is a kind of high-performance film. According to different performances and uses, DAF can be divided into two types: insulating DAF and conductive DAF. The insulating DAF has insulation and can be used to fix chips; the conductive DAF has conductivity and can be used for electrical connection in semiconductor packaging process. In this application, the DAF film is used to fix the chip in the embedded groove 110 of the substrate.

[0063] S104, using a dry film lamination process, the photoresist material is pressed into the flexible groove 120 and the gap 112, and a photoresist film layer 20 is formed on the surface of the substrate.

[0064] Figure 2D The cross-sectional view after forming the photoresist film layer 20 by the dry film lamination process is shown. The photoresist material pressed into the flexible groove 120 forms a flexible structure 210.

[0065] The dry film lamination process can be realized by a vacuum laminator, and the photoresist material can be a photoresist dry film material or a polyimide material. In this step, the photoresist dry film or polyimide film is pressed into the flexible groove and the gap between the embedded chip and the embedded groove under the condition of vacuum heating by the dry film lamination process. The process temperature is determined according to different types of dry films.

[0066] S105, the photoresist film layer 20 is patterned and metalized to form a re-distribution layer 30 for the chip embedded in the embedded groove.

[0067] Figure 2E The cross-sectional view after the photoresist film layer 20 is patterned is shown. As Figure 2E The photoresist film layer 20 is photoetched to expose the chip pad. If it is a photosensitive dry film, it can be directly photoetched, or exposed by oxygen plasma etching method.

[0068] Figure 2F The cross-sectional view of the re-distribution layer 30 after metalization is shown. The metalization can use Ti / Al, Ti / Cu or Ti / Au alloy. When the metal layer (Ti / Al or Ti / Cu or Ti / Au) is prepared, magnetron sputtering or metal evaporation process can be used. The metal layer is patterned to form a re-distribution layer (RDL), which can be etched or commonly used semi-processed RDL customization.

[0069] S106, remove the excess substrate material on both sides of the flexible structure 210 formed in the flexible groove 120.

[0070] Figure 2GThe cross-sectional view shows the removal of the excess substrate material on both sides of the flexible structure 210. The excess substrate material on both sides of the flexible structure formed in the flexible groove can be removed by dry etching, and the etching is performed on the patterned gap of the redistribution layer 30. When a silicon substrate is used, deep silicon etching can be used to remove the excess silicon in the flexible groove to form a pure flexible structure.

[0071] S107, back-thinning the substrate until the flexible structure 210 is exposed.

[0072] Figure 2H The cross-sectional view shows the release of the flexible structure 210 after back-thinning the substrate. The back of the substrate is the other side away from the surface of the substrate. By back-thinning the substrate, the prepared flexible structure 210 can be released.

[0073] Figure 2H The flexible structure formed by the Kirigami structure flexible groove is shown.

[0074] Figure 3 The flexible structure formed by the meander flexible groove is shown.

[0075] Figure 4 The cross-sectional view shows Figures 2A to 2H The top view of the flexible electronic device is shown. The functional unit corresponds to the embedded groove region of the chip, and the parallel parallel groove corresponds to the parallel parallel flexible structure 210. Figure 5 The top view of the flexible structure 210 formed by the Kirigami structure flexible groove is shown. For example, the length L of each opening in the structure is 200 μm, the width W is 50 μm, and the edge thickness S is 10 μm.

[0076] The preparation method of the flexible electronic device provided in the embodiments of the present application can flex the substrate by preparing a flexible structure in the substrate, thereby realizing the flexibility of the electronic device, and obtaining a flexible electronic device with higher performance. Compared with the flexible electronic device prepared by the existing process, the present application has high reliability and can be compatible with the existing scale manufacturing process, thereby meeting the flexible demand of high-performance electronic devices.

[0077] The embodiments of the present application also provide a flexible electronic device, which is prepared by the preparation method of the flexible electronic device in the above embodiments.

[0078] The embodiments of the present application also provide a flexible electronic device, which includes the above flexible electronic device. For example, the flexible electronic device is a foldable mobile phone, a foldable watch, etc.

[0079] In the description of the present disclosure, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like is based on the orientation or positional relationship shown in the drawings, and is only for the purpose of facilitating the description of the present disclosure and simplifying the description, and does not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation of the present disclosure.

[0080] In addition, the terms "first", "second" are only for descriptive purpose, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present disclosure, the meaning of "multiple" is two or more, unless otherwise explicitly specified and limited.

[0081] In the present disclosure, unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connecting", "fixing" and the like should be understood in a broad sense, for example, it can be fixed connection, or detachable connection, or integral; it can be mechanical connection, or electrical connection, or communication; it can be direct connection, or indirect connection through intermediate medium, or internal communication of two elements or interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the present disclosure can be understood according to the specific circumstances.

[0082] In the present disclosure, unless otherwise explicitly specified and limited, the first feature "on" or "under" the second feature can include that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, the first feature "on", "above" and "on" the second feature includes that the first feature is directly above and obliquely above the second feature, or only indicates that the horizontal height of the first feature is higher than that of the second feature. The first feature "under", "below" and "under" the second feature includes that the first feature is directly above and obliquely above the second feature, or only indicates that the horizontal height of the first feature is less than that of the second feature.

[0083] The foregoing disclosure provides many different implementations or examples for carrying out different structures of this disclosure. To simplify this disclosure, the components and arrangements of specific examples are described above. Of course, these are merely examples and are not intended to limit this disclosure. Furthermore, reference numerals and / or reference letters may be repeated in different examples; such repetition is for simplification and clarity and does not in itself indicate a relationship between the various implementations and / or arrangements discussed.

[0084] The above are merely specific embodiments of this disclosure, but the scope of protection of this disclosure is not limited thereto. Any person skilled in the art can easily conceive of various variations or substitutions within the technical scope disclosed in this disclosure. Different parts of different embodiments can be combined with each other without conflict, and these should all be covered within the scope of protection of this disclosure. Therefore, the scope of protection of this disclosure should be determined by the scope of the claims.

Claims

1. A method for fabricating a flexible electronic device, characterized in that, include: Provide substrate; The surface of the substrate is patterned to form embedded grooves and flexible grooves; there are multiple embedded grooves, which are located on both sides of the flexible grooves. The chip is attached to the embedding groove, and there is a gap between the chip and the sidewall of the embedding groove; Using a dry film lamination process, photolithography material is pressed into the flexible groove and the gap to form a photolithography film layer covering the surface of the substrate. The photolithography layer is patterned and metal wiring is performed to form a redistribution layer for the chip embedded in the buried trench; Remove excess substrate material from both sides of the flexible structure formed in the flexible groove; The substrate is thinned on the back until the flexible structure is exposed.

2. The method for fabricating a flexible electronic device according to claim 1, characterized in that, The flexible groove is a spiral-shaped flexible groove, a paper-cutting structure flexible groove, or a folding structure flexible groove.

3. The method for fabricating a flexible electronic device according to claim 1, characterized in that, The depths of the embedded groove and the flexible groove may be the same or different.

4. The method for fabricating a flexible electronic device according to claim 1, characterized in that, The step of attaching the chip into the embedding groove includes: The chip with a die-attach film on its back is attached into the embedding groove using a flip-chip bonding machine or a submicron placement machine.

5. The method for fabricating a flexible electronic device according to claim 1, characterized in that, The photolithography material is either a dry film photolithography material or a polyimide material.

6. The method for fabricating a flexible electronic device according to claim 1, characterized in that, The metal wiring uses Ti / Al, Ti / Cu or Ti / Au alloy.

7. The method for fabricating a flexible electronic device according to claim 1, characterized in that, The removal of excess substrate material from both sides of the flexible structure formed in the flexible groove includes: Excess substrate material on both sides of the flexible structure formed in the flexible trench is removed by dry etching.

8. The method for fabricating a flexible electronic device according to claim 1, characterized in that, The substrate is a silicon substrate.

9. A flexible electronic device, characterized in that, The flexible electronic device is prepared using the method for preparing a flexible electronic device according to any one of claims 1 to 8.

10. A flexible electronic device, characterized in that, The flexible electronic device includes the flexible electronic device according to claim 9.

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