US20080257586A1

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Publication number: US20080257586A1
Application number: US11/770,878
Authority: US
Inventors: Yu-Hua Chen; Ying-Ching Shih
Original assignee: Industrial Technology Research Institute ITRI
Current assignee: Industrial Technology Research Institute ITRI
Priority date: 2007-04-18
Filing date: 2007-06-29
Publication date: 2008-10-23
Also published as: US20120043115A1; TW200843570A; US8513532B2; TWI339087B

Abstract

A manufacturing method of a flexible circuit structure with stretchability includes the following steps. A plurality of compressible flexible bumps is formed on a flexible substrate; next, a metal circuit is formed on the flexible substrate and each of the compressible flexible bumps. When an external tensile force is applied on the flexible substrate, the capability of the metal circuit in withstanding the external tensile force is improved due to flexibility of the compressible flexible bumps, and thus, the stretchability of the flexible circuit is improved.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This non-provisional application claims priority under 35 U.S.C. § 119(a) on Patent Application No(s). 096113690 filed in Taiwan, R.O.C. on Apr. 18, 2007, the entire contents of which are hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a flexible circuit structure and a method of manufacturing the same, and more particularly to a flexible circuit structure with stretchability and a method of manufacturing the same.

In. U.S. Pat. No. 6,743,982, a circuit is manufactured on a removable dielectric substrate. The circuit is formed by depositing two different metal materials. Then, the dielectric substrate under the circuit is removed. Thus, a coiled circuit structure is formed through deformation caused by different stress gradients of the metals, so as to achieve an overall stretchable effect.

In US Patent Publication No. US20040192082, a metal circuit is deposited on a pre-stretched flexible substrate. Then, the flexible substrate is released, so as to form a wave-shaped metal circuit structure. Upon being stretched by an external force in a specific direction, the wave-shaped metal circuit structure will be deformed accordingly, so as to prevent a break circuit from occurring to the metal circuit.

In both US Patent Publication No. US20040238819 and US Patent Publication No. US20040243204, a wave-shaped or saw tooth-shaped metal circuit is deposited on a flexible substrate, such that the stretchability of the metal circuit in the longitudinal or transverse direction is improved due to the deformation of the metal circuit. In the US Patent Publication No. US20040238819, the flexible substrate is firstly etched into a wave-shaped structure in a vertical direction, and then, the metal circuit is deposited on the wave-shaped flexible substrate, so as to improve the stretchability of the metal circuit.

According to the above methods, in most cases, the structural shape or material of the circuit is changed to enable the circuit to have better stretchability. However, the external stresses are mainly withstood by the circuit structure directly, so that the stretchability of the circuit structure is limited. Moreover, as an etching process is applied in most circuit process, if the width of the circuit is too small, the etching process becomes quite difficult to be achieved. Therefore, it is still an important trend for persons of this field to improve the stretchability of the circuit and to provide more convenient manufacturing methods.

SUMMARY OF THE INVENTION

Accordingly, the present invention is mainly directed to a flexible circuit structure with stretchability and a method of manufacturing the same. By supporting a circuit with island-shaped flexible bumps, when a flexible substrate is deformed under an external force, the circuit has better stretchability due to the supporting of the island structure together with a curved structure of the circuit, and thus, the stretchability of the flexible circuit is improved. Moreover, through using a method of circuit implantation, the flexible circuit can be manufactured more conveniently.

The present invention provides a flexible circuit structure with stretchability, which includes: a flexible substrate, a plurality of flexible bumps formed on the flexible substrate as independent structures or as an integrated structure, a metal layer formed on the flexible bumps and the flexible substrate, and a flexible material layer disposed on the metal layer.

Moreover, the present invention further provides a method of manufacturing a flexible circuit with stretchability, which includes: providing a supporting substrate; providing a flexible substrate on the supporting substrate; forming a plurality of flexible bumps on the flexible substrate; forming a metal layer on the flexible substrate and the flexible bumps; and forming a flexible material layer on the metal layer.

Through the flexible circuit structure with stretchability and the method of manufacturing the same, when the flexible substrate bears an external tensile force and is deformed, the flexible bumps on the flexible substrate are meanwhile compressed in a vertical direction, so that the flexible substrate is deformed in a horizontal direction. Therefore, the circuit above the flexible bumps only changes from a 3D circuit into the one in the same plane, but the break circuit will not occur though there is an external stretch. Thus, the flexible circuit has better stretchability, and the flexible circuit can be manufactured more conveniently through circuit implantation.

Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from the detailed description given herein below for illustration only, which thus is not limitative of the present invention, and wherein:

FIG. 1A is a schematic sectional view of a flexible circuit structure according to a first embodiment of the present invention;

FIG. 1B is a schematic sectional view of the flexible circuit structure according to the first embodiment of the present invention;

FIG. 1C is a schematic sectional view of the flexible circuit structure according to the first embodiment of the present invention;

FIG. 2A is a schematic sectional view of a flexible circuit structure according to a second embodiment of the present invention;

FIG. 2B is a schematic sectional view of the flexible circuit structure according to the second embodiment of the present invention;

FIG. 2C is a schematic sectional view of the flexible circuit structure according to the second embodiment of the present invention;

FIG. 2D is a schematic sectional view of the flexible circuit structure according to the second embodiment of the present invention;

FIG. 3A is a schematic sectional view of a flexible circuit structure according to a third embodiment of the present invention;

FIG. 3B is a schematic sectional view of the flexible circuit structure according to the third embodiment of the present invention;

FIG. 3C is a schematic sectional view of the flexible circuit structure according to the third embodiment of the present invention;

FIG. 4A is a schematic sectional view of a flexible circuit structure according to a fourth embodiment of the present invention;

FIG. 4B is a schematic sectional view of the flexible circuit structure according to the fourth embodiment of the present invention;

FIG. 4C is a schematic sectional view of the flexible circuit structure according to the fourth embodiment of the present invention;

FIG. 5A is a schematic sectional view of a flexible circuit structure according to a fifth embodiment of the present invention;

FIG. 5B is a schematic sectional view of the flexible circuit structure according to the fifth embodiment of the present invention;

FIG. 5C is a schematic sectional view of the flexible circuit structure according to the fifth embodiment of the present invention;

FIG. 6A is a schematic sectional view of a flexible circuit structure according to a sixth embodiment of the present invention;

FIG. 6B is a schematic view of the flexible circuit structure that is deformed under an external force according to the sixth embodiment of the present invention;

FIG. 7 is a schematic top view of a flexible circuit according to a seventh embodiment of the present invention;

FIG. 8 is a flow chart of a method of manufacturing the flexible circuit according to the first embodiment of the present invention;

FIG. 9 is a flow chart of a method of manufacturing the flexible circuit according to the second embodiment of the present invention;

FIG. 10 is a flow chart of a method of manufacturing the flexible circuit according to the fourth embodiment of the present invention; and

FIG. 11 is a flow chart of a method of manufacturing the flexible circuit according to the eighth embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

FIGS. 1A,1B, and1C are respectively schematic sectional views of a flexible circuit structure according to a first embodiment of the present invention. As shown inFIG. 1C, the flexible circuit structure with stretchability of the present invention includes aflexible substrate20, a plurality offlexible bumps30, ametal layer40, and aflexible material layer50.

Firstly, as shown inFIG. 1A, in the flexible circuit structure with stretchability of the present invention, theflexible substrate20 is attached on a supportingsubstrate10 through a thermal release manner or a UV release manner. The material of theflexible substrate20 includes polyimide (PI) or polydimethylsiloxane (PDMS). Then, a plurality of compressibleflexible bumps30 is deposited on theflexible substrate20 at predetermined positions for implanting the metal circuit, and the compressibility of theflexible bumps30 is higher than that of theflexible substrate20. The material of theflexible bumps30 includes polyimide (PI), polydimethylsiloxane (PDMS), or polyurethane (PU). Theflexible bumps30 are in a substantially island-shaped structure, and persons skilled in the art can easily understand that theflexible bumps30 can also be designed into triangular, semicircular, wave-shaped, or another geometrical shape.

Referring toFIG. 1B, after theflexible bumps30 has been deposited, the metal circuit is implanted on theflexible substrate20 and theflexible bumps30, so as to form themetal layer40, which is used for transmitting signals. Next, referring toFIG. 1C, a layer of flexible material is covered or laminated onto themetal layer40, so as to form theflexible material layer50, and thus, the stability of the flexible circuit structure is improved. Then, the supportingsubstrate10 below theflexible substrate20 is removed. The material of theflexible material layer50 includes polyimide (PI) or polydimethylsiloxane (PDMS).

FIGS. 2A,2B,2C, and2D are respectively schematic sectional views of a flexible circuit structure according to a second embodiment of the present invention. As shown inFIG. 2D, the flexible circuit structure with stretchability of the present invention includes aflexible substrate20, a plurality offlexible bumps30, ametal layer40, aflexible material layer50, and abuffer layer60.

Firstly, as shown inFIG. 2A, in the flexible circuit structure with stretchability of the present invention, theflexible substrate20 is attached on a supportingsubstrate10 through the thermal release manner or the UV release manner. The material of theflexible substrate20 includes polyimide (PI) or polydimethylsiloxane (PDMS). Then, a plurality of compressibleflexible bumps30 is deposited on theflexible substrate20 at predetermined positions for implanting the metal circuit, and the compressibility of theflexible bumps30 is higher than that of theflexible substrate20. The material of theflexible bumps30 includes polyimide (PI), polydimethylsiloxane (PDMS), or polyurethane (PU). Theflexible bumps30 are in a substantially island-shaped structure, and persons skilled in the art can easily understand that theflexible bumps30 can also be designed into triangular, semicircular, wave-shaped, or another geometrical shape.

Referring toFIG. 2B, after theflexible bumps30 has been deposited, a material with a low adherence is coated on the surfaces of theflexible substrate20 and theflexible bumps30, so as to form thebuffer layer60. Next, referring toFIG. 2C, thebuffer layer60 above theflexible bumps30 is removed, and a metal circuit is implanted above thebuffer layer60 and theflexible bumps30, so as to form ametal layer40, which is used for transmitting signals. Next, referring toFIG. 2D, a layer of flexible material is covered or laminated onto themetal layer40, so as to form theflexible material layer50, and thus, the stability of the flexible circuit structure is improved. Then, the supportingsubstrate10 below theflexible substrate20 is removed. The material of theflexible material layer50 includes polyimide (PI) or polydimethylsiloxane (PDMS).

FIGS. 3A,3B, and3C are respectively schematic sectional views of a flexible circuit structure according to a third embodiment of the present invention. The difference between the third embodiment and the first embodiment lies in that theflexible bumps31 are interconnected, i.e., theflexible bumps31 are of an integrated structure. Other structures, materials, and manufacturing processes of the third embodiment are the same as those of the first embodiment, and are not described again herein. In addition, persons skilled in the art can readily understand that theflexible bumps30 of the second embodiment can also be designed to have the same structure as theflexible bumps31 of the third embodiment do.

FIGS. 4A,4B, and4C are respectively schematic sectional views of a flexible circuit structure according to a fourth embodiment of the present invention. As shown inFIG. 4C, the flexible circuit structure with stretchability of the present invention includes aflexible substrate20, a plurality offlexible bumps30, ametal layer40, a firstflexible material layer51, a secondflexible material layer52, anactive element70, and viaholes80.

Firstly, as shown inFIG. 4A, in the flexible circuit structure with stretchability of the present invention, theflexible substrate20 is attached on a supportingsubstrate10 through the thermal release manner or the UV release manner. The material of theflexible substrate20 includes polyimide (PI) or polydimethylsiloxane (PDMS). Then, the active element70 (e.g., a chip) is disposed on the surface of theflexible substrate20 in a direction facing theflexible substrate20. Next, the firstflexible material layer51 is implanted on theactive element70 and theflexible substrate20. In other words, theactive element70 is embedded in the firstflexible material layer51, and at least one viahole80 is formed in the firstflexible material layer51, so as to extend the circuit from a contact of theactive element70 to the firstflexible material layer51. The material of the firstflexible material layer51 includes polyimide (PI) or polydimethylsiloxane (PDMS).

Then, a plurality of compressibleflexible bumps30 is deposited on the firstflexible material layer51 at predetermined positions for implanting the metal circuit, and the compressibility of theflexible bumps30 is higher than that of theflexible substrate20. The material of theflexible bumps30 includes polyimide (PI), polydimethylsiloxane (PDMS), or polyurethane (PU). Theflexible bumps30 are in a substantially island-shaped structure, and persons skilled in the art can easily understand that theflexible bumps30 can also be designed into triangular, semicircular, wave-shaped, or another geometrical shape. In addition, persons skilled in the art can readily understand that theflexible bumps30 of the fourth embodiment can also be designed to have the same structure as theflexible bumps31 of the third embodiment do.

Referring toFIG. 4B, after theflexible bumps30 have been deposited, the metal circuit is implanted on the firstflexible material layer51 and theflexible bumps30, so as to form themetal layer40, which is used for transmitting signals. Next, referring toFIG. 4C, a layer of flexible material is covered or laminated onto themetal layer40, so as to form the secondflexible material layer52, and thus, the stability of the flexible circuit structure is improved. Then, the supportingsubstrate10 below theflexible substrate20 is removed. The material of the secondflexible material layer52 includes polyimide (PI) or polydimethylsiloxane (PDMS).

FIGS. 5A,5B, and5C are respectively schematic sectional views of a flexible circuit structure according to a fifth embodiment of the present invention. As shown inFIG. 5C, the flexible circuit structure with stretchability of the present invention includes aflexible substrate20, a plurality offlexible bumps30, ametal layer40, aflexible material layer50, anactive element70, and pins81.

Firstly, as shown inFIG. 5A, in the flexible circuit structure with stretchability of the present invention, theflexible substrate20 is attached on a supportingsubstrate10 through the thermal release manner or the UV release manner. The material of theflexible substrate20 includes polyimide (PI) or polydimethylsiloxane (PDMS). Then, a plurality of compressibleflexible bumps30 is deposited on theflexible substrate20 at predetermined positions for implanting the metal circuit, and the compressibility of theflexible bumps30 is higher than that of theflexible substrate20. The material of theflexible bumps30 includes polyimide (PI), polydimethylsiloxane (PDMS), or polyurethane (PU). Theflexible bumps30 are in a substantially island-shaped structure, and persons skilled in the art can easily understand that theflexible bumps30 can also be designed into triangular, semicircular, wave-shaped, or another geometrical shape. In addition, persons skilled in the art can readily understand that theflexible bumps30 of the fifth embodiment can also be designed to have the same structure as theflexible bumps31 of the third embodiment do.

After theflexible bumps30 have been deposited, the metal circuit is implanted on the firstflexible material layer51 and theflexible bumps30, so as to form themetal layer40, which is used for transmitting signals. Referring toFIG. 5B, the active element70 (e.g., a chip) is disposed above themetal layer40, and thepins81 are electrically coupled to the correspondingmetal layer40 respectively. Next, referring toFIG. 5C, theflexible material layer50 is implanted on theactive element70 and themetal layer40, so as to improve the stability of the flexible circuit structure. In other words, theactive element70 is embedded in theflexible material layer50. The material of theflexible material layer50 includes polyimide (PI) or polydimethylsiloxane (PDMS).

FIG. 6A is a schematic sectional view of a flexible circuit structure according to a sixth embodiment of the present invention. The difference between the sixth embodiment and the second embodiment lies in that thebuffer layer60 is substituted by asacrificial layer61 in the sixth embodiment. After themetal layer40 is implanted, thebuffer layer60 is removed, such that themetal layer40 turns into a suspending configuration, and the suspending area is thesacrificial layer61. In other words, themetal layer40 between theflexible bumps30 is in a suspending configuration. In the sixth embodiment, theflexible bumps30 have a semicircular structure, and the structure of the rest parts is the same as that of the second embodiment, which thus is not described again here.

FIG. 6B is a schematic view of the flexible circuit structure that is deformed under an external force according to the sixth embodiment of the present invention. When a horizontal external force is applied on theflexible substrate20, the force is mostly absorbed by the semicircular flexible bumps30. Accordingly, theflexible bumps30 is deformed under the external force, which enhances the stretchability of themetal layer40, and reduces the possibility that themetal layer40 is broken due to the external force.

FIG. 7 is a schematic top view of a flexible circuit according to a seventh embodiment of the present invention. As shown inFIG. 7, themetal layer40 on theflexible substrate20 is in a wave-shaped structure in the seventh embodiment. A plurality offlexible bumps30 is formed on the twist-and-turn path of themetal layer40, and every twoflexible bumps30 are spaced apart by a predetermined distance. The difference between the seventh embodiment and the first embodiment lies in that, in the seventh embodiment, themetal layer40 is firstly formed on theflexible substrate20, and then, the flexible bumps are deposited on themetal layer40. The materials of the rest parts are the same as those in the first embodiment, which thus will not be described again here.

FIG. 8 is a flow chart of a method of manufacturing the flexible circuit according to the first embodiment of the present invention. As shown inFIG. 8, the method of manufacturing the flexible circuit with stretchability of the present invention includes the following steps.

Firstly, a supporting substrate is provided (Step100). Then, a flexible substrate is provided on the supporting substrate (Step101). The material of the flexible substrate includes polyimide (PI) or polydimethylsiloxane (PDMS), and the flexible substrate is attached on the supporting substrate through the thermal release manner or the UV release manner.

Next, a plurality of flexible bumps is formed on the flexible substrate (Step102). The material of the flexible bumps includes polyimide (PI) or polydimethylsiloxane (PDMS), and the flexible bumps are deposited on the flexible substrate. The flexible bumps can be in independent structures, or be interconnected to an integrated structure.

Then, a metal layer is formed on the flexible substrate and the flexible bumps (Step103). The material of the metal layer can be, for example, conductive materials such as Au, Ag, or Cu, and the metal layer is formed on the flexible substrate and the flexible bumps by means of implantation, which is used for transmitting signals.

Then, a flexible material layer is formed on the metal layer (Step104). The material of the flexible material layer includes polyimide (PI) or polydimethylsiloxane (PDMS), and the flexible material layer is formed on the metal layer by means of covering or laminating, so as to improve the stability of the flexible circuit structure. Finally, the supporting substrate below the flexible substrate is removed (Step105). In addition, persons skilled in the art can readily understand that, the sequence ofStep104 andStep105 can be exchanged, i.e., it still falls into the scope of the present invention that the flexible material is formed on the metal layer after the supporting substrate has been removed.

FIG. 9 is a flow chart of a method of manufacturing the flexible circuit according to the second embodiment of the present invention. As shown inFIG. 9, the method of manufacturing the flexible circuit with stretchability of the present invention includes the following steps.

Firstly, a supporting substrate is provided (Step200). Then, a flexible substrate is provided on the supporting substrate (Step201). The material of the flexible substrate includes polyimide (PI) or polydimethylsiloxane (PDMS), and the flexible substrate is attached on the supporting substrate through the thermal release manner or the UV release manner.

Next, a plurality of flexible bumps is formed on the flexible substrate (Step202). The material of the flexible bumps includes polyimide (PI) or polydimethylsiloxane (PDMS), and the flexible bumps are deposited on the flexible substrate. The flexible bumps can be in independent structures, or be interconnected to an integrated structure.

Then, a buffer layer is formed on the flexible substrate and the flexible bumps (Step203). The buffer layer has a low adherence, and is formed on the flexible substrate and the flexible bumps by coating, so as to bear the external stresses between the flexible substrate and a metal layer. Next, the buffer layer above each flexible bump is removed (Step204).

Then, the metal layer is formed on the buffer layer and the flexible bumps (Step205). The material of the metal layer can be, for example, conductive materials such as Au, Ag, or Cu. The metal layer is formed on the flexible substrate and the flexible bumps by means of implantation, which is used for transmitting signals.

Then, a flexible material layer is formed on the metal layer (Step206). The material of the flexible material layer includes polyimide (PI) or polydimethylsiloxane (PDMS), and the flexible material layer is formed on the metal layer by means of covering or laminating, so as to improve the stability of the flexible circuit structure. Finally, the supporting substrate below the flexible substrate is removed (Step207). In addition, persons skilled in the art can readily understand that, the sequence ofStep206 andStep207 can be exchanged, i.e., it still falls into the scope of the present invention that the flexible material layer is formed on the metal layer after the supporting substrate is removed.

FIG. 10 is a flow chart of a method of manufacturing the flexible circuit according to the fourth embodiment of the present invention. As shown inFIG. 10, the method of manufacturing the flexible circuit with stretchability of the present invention includes the following steps.

Firstly, a supporting substrate is provided (Step300). Then, a flexible substrate is provided on the supporting substrate (Step301). The material of the flexible substrate includes polyimide (PI) or polydimethylsiloxane (PDMS), and the flexible substrate is attached on the supporting substrate through the thermal release manner or the UV release manner.

Next, an active element (e.g., a chip) is disposed on the flexible substrate (Step302). Then, a first flexible material layer is formed on the active element and the flexible substrate (Step303). The material of the first flexible material layer includes polyimide (PI) or polydimethylsiloxane (PDMS).

Then, at least one via hole is formed in the first flexible material layer (Step304), so as to extend the circuit from a contact of the active element to the first flexible material layer. Then, a plurality of flexible bumps is formed on the first flexible material layer (Step305). The material of the flexible bumps includes polyimide (PI) or polydimethylsiloxane (PDMS), and the flexible bumps are deposited on the flexible substrate. The flexible bumps can be in independent structures, or be interconnected to an integrated structure.

Then, a metal layer is formed on the first flexible material layer and the flexible bumps (Step306). The material of the metal layer can be, for example, conductive materials such as Au, Ag, or Cu, and the metal layer is formed on the flexible substrate and the flexible bumps by means of implantation, which is used for transmitting signals.

Then, a second flexible material layer is formed on the metal layer (Step307). The material of the second flexible material layer includes polyimide (PI) or polydimethylsiloxane (PDMS), and the second flexible material layer is formed on the metal layer by means of covering or laminating, so as to improve the stability of the flexible circuit structure. Finally, the supporting substrate below the flexible substrate is removed (Step308). In addition, persons skilled in the art can readily understand that the sequence ofStep307 andStep308 can be exchanged, i.e., it still falls into the scope of the present invention that the second flexible material layer is formed on the metal layer after the supporting substrate is removed.

FIG. 11 is a flow chart of a method of manufacturing the flexible circuit according to the eighth embodiment of the present invention. As shown inFIG. 11, the method of manufacturing the flexible circuit with stretchability of the present invention includes the following steps.

Firstly, a supporting substrate is provided (Step400). Then, a flexible substrate is provided on the supporting substrate (Step401). The material of the flexible substrate includes polyimide (PI) or polydimethylsiloxane (PDMS), and the flexible substrate is attached on the supporting substrate through the thermal release manner or the UV release manner.

Next, an active element (e.g., a chip) is disposed on the flexible substrate (Step402). Then, a first flexible material layer is formed on the active element and the flexible substrate (Step403). The material of the first flexible material layer includes polyimide (PI) or polydimethylsiloxane (PDMS).

Then, at least one via hole is formed in the first flexible material layer (Step404), so as to extend the circuit from a contact of the active element to the first flexible material layer. Then, a plurality of flexible bumps is formed on the first flexible material layer (Step405). The material of the flexible bumps includes polyimide (PI) or polydimethylsiloxane (PDMS), and the flexible bumps are deposited on the flexible substrate. The flexible bumps can be in independent structures, or be interconnected to an integrated structure.

Then, a buffer layer is formed on the first flexible material layer and the flexible bumps (Step406). The buffer layer has a low adherence, and is formed on the first flexible material layer and the flexible bumps by means of coating, so as to bear the external stresses between the flexible substrate and a metal layer. Then, the buffer layer above each flexible bump is removed (Step407).

Then, the metal layer is formed on the buffer layer and the flexible bumps (Step408). The material of the metal layer can be, for example, conductive materials such as Au, Ag, or Cu, and the metal layer is formed on the buffer layer and the flexible bumps by means of implantation, which is used for transmitting signals.

Then, a second flexible material layer is formed on the metal layer (Step409). The material of the second flexible material layer includes polyimide (PI) or polydimethylsiloxane (PDMS), and the second flexible material layer is formed on the metal layer by means of covering or laminating, so as to improve the stability of the flexible circuit structure. Finally, the supporting substrate below the flexible substrate is removed (Step410). In addition, persons skilled in the art can readily understand that, the sequence ofStep409 andStep410 can be exchanged, i.e., it still falls into the scope of the present invention that the second flexible material layer is formed on the metal layer after the supporting substrate is removed.

To sum up, according to the flexible circuit structure with stretchability of the present invention and the method of manufacturing the same, a plurality of flexible bumps is formed on the flexible substrate, and then, the designed circuit is formed on the flexible substrate and the flexible bumps. Once the flexible substrate is deformed under an external force, the flexible bumps on the flexible substrate are compressed accordingly in the vertical direction, so as to provide a deformation of the flexible substrate in the horizontal direction. Therefore, the circuit on the flexible bumps has gradually changed from a 3D circuit into the one on the same plane, but the break circuit will not occur though there is an external stretch. Thus, the flexible circuit has better stretchability, and the flexible circuit can be manufactured more conveniently by means of circuit implantation.

The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.

Claims

1. A flexible circuit structure with stretchability, comprising:

a flexible substrate;

a plurality of flexible bumps, formed on the flexible substrate; and

a metal layer, formed on the flexible bumps and the flexible substrate.

2. The flexible circuit structure with stretchability as claimed inclaim 1, further comprising a flexible material layer disposed on the metal layer.

3. The flexible circuit structure with stretchability as claimed inclaim 1, further comprising a buffer layer disposed between the flexible bumps and the metal layer.

4. The flexible circuit structure with stretchability as claimed inclaim 1, further comprising a sacrificial layer disposed between the flexible bumps and the metal layer, such that the metal layer between the flexible bumps is in a suspending form.

5. The flexible circuit structure with stretchability as claimed inclaim 1, wherein a material of the flexible substrate includes polyimide (PI) or polydimethylsiloxane (PDMS).

6. The flexible circuit structure with stretchability as claimed inclaim 1, wherein a material of the flexible material layer includes polyimide (PI) or polydimethylsiloxane (PDMS).

7. The flexible circuit structure with stretchability as claimed inclaim 1, wherein a material of the flexible bumps includes polyimide (PI), polydimethylsiloxane (PDMS), or polyurethane (PU).

8. The flexible circuit structure with stretchability as claimed inclaim 1, wherein the flexible bumps have a higher compressibility than the flexible substrate.

9. The flexible circuit structure with stretchability as claimed inclaim 1, wherein the flexible bumps are in an integrated structure.

10. The flexible circuit structure with stretchability as claimed inclaim 1, wherein the flexible bumps are in a substantially island-shaped structure.

11. A flexible circuit structure with stretchability, comprising:

a flexible substrate;

a metal layer, formed on the flexible substrate; and

a plurality of flexible bumps, formed on the metal layer and the flexible substrate.

12. The flexible circuit structure with stretchability as claimed inclaim 11, wherein the metal layer has a wave-shaped structure.

13. The flexible circuit structure with stretchability as claimed inclaim 11, wherein a material of the flexible substrate includes polyimide (PI) or polydimethylsiloxane (PDMS).

14. The flexible circuit structure with stretchability as claimed inclaim 11, wherein a material of the flexible material layer includes polyimide (PI) or polydimethylsiloxane (PDMS).

15. The flexible circuit structure with stretchability as claimed inclaim 11, wherein a material of the flexible bumps includes polyimide (PI), polydimethylsiloxane (PDMS), or polyurethane (PU).

16. The flexible circuit structure with stretchability as claimed inclaim 11, wherein the flexible bumps have a higher compressibility than the flexible substrate.

17. A flexible circuit structure with stretchability, comprising:

a flexible substrate;

an active element, disposed on the flexible substrate;

a first flexible material layer, formed on the active element and the flexible substrate;

a plurality of flexible bumps, formed on the flexible substrate; and

a metal layer, formed on the flexible bumps and the flexible substrate.

18. The flexible circuit structure with stretchability as claimed inclaim 17, further comprising a flexible material layer disposed on the metal layer.

19. The flexible circuit structure with stretchability as claimed inclaim 17, further comprising a buffer layer formed between the flexible bumps and the metal layer.

20. The flexible circuit structure with stretchability as claimed inclaim 17, wherein a material of the flexible substrate includes polyimide (PI) or polydimethylsiloxane (PDMS).

21. The flexible circuit structure with stretchability as claimed inclaim 17, wherein materials of the first and second flexible material layers include polyimide (PI) or polydimethylsiloxane (PDMS).

22. The flexible circuit structure with stretchability as claimed inclaim 17, wherein a material of the flexible bumps includes polyimide (PI), polydimethylsiloxane (PDMS), or polyurethane (PU).

23. The flexible circuit structure with stretchability as claimed inclaim 17, wherein the flexible bumps have a higher compressibility than the flexible substrate.

24. The flexible circuit structure with stretchability as claimed inclaim 17, wherein the flexible bumps are in an integrated structure.

25. The flexible circuit structure with stretchability as claimed inclaim 17, wherein the flexible bumps are in a substantially island-shaped structure.

26. A method of manufacturing a flexible circuit with stretchability, comprising:

providing a supporting substrate;

providing a flexible substrate on the supporting substrate;

forming a plurality of flexible bumps on the flexible substrate;

forming a metal layer on the flexible substrate and the flexible bumps; and

forming a flexible material layer on the metal layer.

27. The method of manufacturing the flexible circuit with stretchability as claimed inclaim 26, further comprising removing the supporting substrate after forming the flexible material layer on the metal layer.

28. The method of manufacturing the flexible circuit with stretchability as claimed inclaim 26, after forming the plurality of flexible bumps on the flexible substrate, further comprising:

forming a buffer layer on the flexible substrate and the flexible bumps; and

removing the buffer layer on the flexible bumps.

29. The method of manufacturing the flexible circuit with stretchability as claimed inclaim 26, wherein the flexible substrate is attached on the supporting substrate through a thermal release manner or a UV release manner.

30. The method of manufacturing the flexible circuit with stretchability as claimed inclaim 26, wherein a material of the flexible substrate includes polyimide (PI) or polydimethylsiloxane (PDMS).

31. The method of manufacturing the flexible circuit with stretchability as claimed inclaim 26, wherein a material of the flexible material layer includes polyimide (PI) or polydimethylsiloxane (PDMS).

32. The method of manufacturing the flexible circuit with stretchability as claimed inclaim 26, wherein a material of the flexible bumps includes polyimide (PI), polydimethylsiloxane (PDMS), or polyurethane (PU).

33. The method of manufacturing the flexible circuit with stretchability as claimed inclaim 26, wherein the flexible bumps have a higher compressibility than the flexible substrate.

34. The method of manufacturing the flexible circuit with stretchability as claimed inclaim 26, wherein the flexible bumps are in an integrated structure.

35. A method of manufacturing a flexible circuit with stretchability, comprising:

providing a supporting substrate;

providing a flexible substrate on the supporting substrate;

disposing an active element on the flexible substrate;

forming a first flexible material layer on the active element and the flexible substrate;

forming at least one via hole in the first flexible material layer;

forming a plurality of flexible bumps on the first flexible material layer; and

forming a metal layer on the first flexible material layer and the flexible bumps; and

forming a second flexible material layer on the metal layer.

36. The method of manufacturing the flexible circuit with stretchability as claimed inclaim 35, further comprising removing the supporting substrate after forming a second flexible material layer on the metal layer.

37. The method of manufacturing the flexible circuit with stretchability as claimed inclaim 35, after forming the plurality of flexible bumps on the flexible substrate, further comprising:

covering a buffer layer on the flexible substrate and the flexible bumps; and

removing the buffer layer on the flexible bumps.

38. The method of manufacturing the flexible circuit with stretchability as claimed inclaim 35, wherein the flexible substrate is attached on the supporting substrate through a thermal release manner or a UV release manner.

39. The method of manufacturing the flexible circuit with stretchability as claimed inclaim 35, wherein a material of the flexible substrate includes polyimide (PI) or polydimethylsiloxane (PDMS).

40. The method of manufacturing the flexible circuit with stretchability as claimed inclaim 35, wherein materials of the first and second flexible material layers include polyimide (PI) or polydimethylsiloxane (PDMS).

41. The method of manufacturing the flexible circuit with stretchability as claimed inclaim 35, wherein a material of the flexible bumps includes polyimide (PI), polydimethylsiloxane (PDMS), or polyurethane (PU).

42. The method of manufacturing the flexible circuit with stretchability as claimed inclaim 35, wherein the flexible bumps have a higher compressibility than the flexible substrate.

43. The method of manufacturing the flexible circuit with stretchability as claimed inclaim 35, wherein the flexible bumps are in an integrated structure.