TWI662594B - Flexible substrate and circuit structure and method of manufacturing the same - Google Patents

Abstract

A method for manufacturing a flexible substrate and a circuit structure includes the following steps. A release layer is formed on the carrier. At least one wafer is disposed on the release layer. A polymer material is injected to cover at least part of the sidewall of at least one wafer. The polymer material is cured into a polymer substrate. The polymer substrate and the release layer are separated, and at least one wafer is embedded in the polymer substrate. A first circuit structure is formed on the first surface of the polymer substrate, and the first circuit structure is electrically connected to the first pad of at least one wafer.

Description

Flexible substrate and circuit structure and manufacturing method thereof

The invention relates to a flexible substrate, a circuit structure and a manufacturing method thereof.

With the advancement of semiconductor technology, the brightness and efficiency of light emitting diodes (LEDs) have been greatly improved. Therefore, light-emitting diode displays have gradually replaced traditional displays and become a new generation of lighting elements, which are widely used in, for example, home lighting devices, automotive lighting devices, handheld lighting devices, LCD panel backlights, traffic signal indicators, For lighting applications such as signs or advertising boards.

However, in the case of general light-emitting diode wafers, it is easy to cause problems such as wafer shift and wafer rotation due to the unevenness of the circuit board, or it is easy during the transpose process of general light-emitting diode displays. A wafer offset problem has occurred. How to solve the above problems of wafer displacement, rotation or offset will become an important subject in the future.

The invention provides a flexible substrate and a circuit structure and a manufacturing method thereof, which can manufacture a flexible or stretchable circuit substrate structure, and solve the wafer displacement and wafer rotation caused by the unevenness of the circuit board when the wafer is punched. Or improve the problem of chip shift during the transpose process of general light emitting diode displays.

The invention provides a method for manufacturing a flexible substrate and a circuit structure. The steps are as follows. A release layer is formed on the carrier. At least one wafer is disposed on the release layer. A polymer material is injected to cover at least part of the sidewall of at least one wafer. The polymer material is cured into a polymer substrate. The polymer substrate and the release layer are separated, and at least one wafer is embedded in the polymer substrate. A first circuit structure is formed on the first surface of the polymer substrate, and the first circuit structure is electrically connected to the first pad of at least one wafer.

The invention provides a flexible substrate and a circuit structure, including a polymer substrate, a plurality of light-emitting element wafers, and a first circuit structure. The polymer substrate has a first surface and a second surface opposite to each other. A plurality of light-emitting element wafers are embedded in a polymer substrate. The first circuit structure is disposed on the first surface of the polymer substrate. The first pad or the second pad in each light-emitting element wafer is coplanar with the first surface of the polymer substrate.

In order to make the above features and advantages of the present invention more comprehensible, embodiments are hereinafter described in detail with reference to the accompanying drawings.

The invention is explained more fully with reference to the drawings of this embodiment. However, the present invention may be embodied in various forms and should not be limited to the embodiments described herein. The thicknesses of layers and regions in the drawings are exaggerated for clarity. The same or similar reference numerals indicate the same or similar elements, and the following paragraphs will not repeat them one by one.

1A to 1E are schematic perspective views of a manufacturing process of a flexible substrate and a circuit structure according to a first embodiment of the present invention. This embodiment provides a method for manufacturing a flexible substrate and a circuit structure, in which the wafer 100 is embedded in the polymer substrate 108 in a wafer priority molding method. The detailed steps are as follows.

Referring to FIG. 1A, first, a release layer 104 is formed on a carrier 102. In an embodiment, the material of the carrier 102 may be glass, quartz, metal, ceramic or other suitable materials. In some embodiments, the material of the release layer 104 may be a polymer, an organic material, an inorganic material, or a combination thereof. In other embodiments, the release layer 104 may include a solid, liquid, or gel state.

Referring to FIG. 1B, a plurality of wafers 100 are disposed on the release layer 104 by a transposition method. In an embodiment, the transposition method includes an electrostatic method, a vacuum suction method, a pick and place method, a wafer to wafer bonding method, or a sticking method. However, the present invention is not limited to this, as long as any transposition method capable of disposing the wafer 100 on the release layer 104 is within the scope of the present invention. In one embodiment, the wafer 100 may be a micro-emitting diode having a length, a width, and a height of less than 1 millimeter (mm). Because the wafer 100 has a small volume and is easily displaced or rotated during transposition, the release layer 104 can be used to temporarily fix or attach the wafer 100 to the carrier 102 to improve the phenomenon of displacement or rotation. In some embodiments, the material of the release layer 104 includes a material having temporary fixing characteristics. In addition, the number, function, and configuration of the chips 100 can be adjusted according to actual needs. For example, the single wafer 100 in FIG. 1B may be a light-emitting diode that emits a single color. On the other hand, a single wafer 100 in FIG. 1B may include integrating a red light emitting diode, a blue light emitting diode, and a green light emitting diode into a module. In some embodiments, the wafer 100 may be, for example, a light emitting device wafer, an active device wafer, a passive device wafer, or a combination thereof. In alternative embodiments, each wafer 100 may be a wafer having the same function or a wafer having a different function.

Referring to FIGS. 1C and 1D, after the wafer 100 is disposed on the release layer 104, a polymer material 106 is injected to cover the wafer 100. In one embodiment, the polymer material 106 includes Polydimethylsiloxane (PDMS), Polyurethane (PU), Thermoplastic Urethane (TPU), and Polyimide (PI). Or a combination.

Referring to FIG. 1D, the polymer material 106 is cured into a polymer substrate 108. At this time, the first surface 108 a of the polymer substrate 108 faces and contacts the release layer 104. In an embodiment, the curing step is, for example, a heating film-forming treatment, for example, the polymer material 106 is heated to a temperature between 60 ° C. and 220 ° C. to cure or form the polymer material 106. However, the present invention is not limited to this. In other embodiments, the curing method or temperature is different according to the type of the polymer material 106.

1D and FIG. 1E, the polymer substrate 108 and the release layer 104 are separated. Specifically, the polymer substrate 108 and the release layer 104 (or the carrier 102) can be mechanically debond, laser debond, or heating or cooling debond. ) Separate or separate. In this case, the polymer substrate 108 may be turned upside down so that the first surface 108a of the polymer substrate 108 faces upward. As shown in FIG. 1E, the wafer 100 is embedded in the polymer substrate 108, and at least one of the wafers 100 is connected. The pads (such as the pads 208 and 210 shown in FIG. 2B) are exposed on the polymer substrate 108. To some extent, the at least one pad of each wafer 100 can be considered as a coplanar plane, which facilitates subsequent screen printing 110 to further improve the yield of the flexible substrate and the circuit structure.

Next, a screen printing step 110 is performed to form a first circuit structure 112 (as shown in FIG. 2F) on the surface of the polymer substrate 108. In one embodiment, the screen printing step 110 uses the stretchable conductive silver glue and the insulation glue to be spaced apart to print the required multiple layers of different input signal conductive lines, but the invention is not limited thereto. In this embodiment, the step of forming the first circuit structure 112 after the wafer 100 is embedded in the polymer substrate 108 can fix the position of the wafer 100 and make the at least one pad of the wafer 100 coplanar to facilitate the screen printing step. 110. In detail, in this embodiment, the step of transposing the wafer 100 onto the release layer 104 and then injecting the polymer material 106 can reduce the height between the polymer substrate 108 and the wafer 100 embedded in the polymer substrate 108. Poor, thereby solving the problem that the subsequent circuit structure and the chip have an electrical connection offset due to unevenness of the surface or placement of the chip. That is, the yield of the flexible substrate and the circuit structure manufactured by the manufacturing method of this embodiment can be improved.

In addition, after the polymer substrate 108 is separated from the release layer 104 and before the screen printing step 110 is performed, the release layer 104 remaining on the polymer substrate 108 may be selectively removed. In one embodiment, the release layer 104 remaining on the polymer substrate 108 can be removed by ion bombardment or cleaning with a solution (such as alcohol, acetone, or toluene), so that the polymer substrate 108 can be removed. The release layer 104 reduces residue.

2A to 2F are schematic cross-sectional views illustrating a manufacturing process of a flexible substrate and a circuit structure according to a second embodiment of the present invention.

Please refer to FIG. 2A and FIG. 2B. The manufacturing process of the flexible substrate and circuit structure of the second embodiment is basically similar to the manufacturing process of the flexible substrate and circuit structure of the first embodiment. That is, FIG. It has been described in the above paragraphs, and will not be repeated here. The manufacturing process of the flexible substrate and wiring structure of the second embodiment is described by taking the light-emitting element wafer 200 as an example. In this embodiment, the light-emitting element wafer 200 may be a horizontal light-emitting diode. As shown in the enlarged view of FIG. 2B, the light-emitting element wafer 200 includes a first semiconductor layer 202, a light-emitting layer 204, a second semiconductor layer 206, a first pad 208, and a second pad 210. The light emitting layer 204 is formed on the first semiconductor layer 202. The second semiconductor layer 206 is formed on the light emitting layer 204. The first pad 208 is formed on the first semiconductor layer 202. The second pad 210 is formed on the second semiconductor layer 206. In addition, an insulating material (not shown) is provided around the outer edge of the light-emitting element wafer 200 to protect the light-emitting element wafer 200.

Specifically, a method of manufacturing the light-emitting element wafer 200 (hereinafter simply referred to as the wafer 200) is as follows. First, a first semiconductor layer 202, a light emitting layer 204, and a second semiconductor layer 206 are sequentially formed on an epitaxial substrate (not shown). In one embodiment, the conductivity type of the first semiconductor layer 202 is different from that of the second semiconductor layer 206. For example, the first semiconductor layer 202 may be an N-type semiconductor material, and the second semiconductor layer 206 may be a P-type semiconductor material; and vice versa. In some embodiments, the material of the light emitting layer 204 may be, for example, a multiple quantum well light emitting material. Then, a part of the second semiconductor layer 206 and a part of the light emitting layer 204 are removed to expose a part of the surface of the first semiconductor layer 202. Next, a first pad 208 is formed on a part of the surface of the first semiconductor layer 202, and a second pad 210 is formed on the surface of the second semiconductor layer 206. In one embodiment, the first pad 208 and the second pad 210 may be the same material, such as a conductive material. In this embodiment, the second pad 210 is higher than the first pad 208, and there is a height difference H1 between the top surface 208t of the first pad 208 and the top surface 210t of the second pad 210. In one embodiment, the height difference H1 is about 1 micrometer (μm), but not limited thereto.

As shown in FIG. 2B, a plurality of wafers 200 are disposed on the release layer 104 by a transposition method. In detail, first, the wafer 200 is turned upside down so that the top surface 208t of the first pad 208 and the top surface 210t of the second pad 210 face the release layer 104. In one embodiment, the top surface 210t of the second pad 210 abuts or contacts the release layer 104, and the top surface 208t of the first pad 208 is separated from the release layer 104 by a distance. The above steps can be considered as a method of disposing the wafer 200 on the release layer 104 in a pad-down manner. Although FIG. 2B shows only three wafers 200, the present invention is not limited thereto. In other embodiments, the number and configuration of the wafers 200 can be adjusted as required. In alternative embodiments, the wafers 200 may be arranged in an array.

Referring to FIG. 2C, after the wafer 200 is disposed on the release layer 104, a polymer material 106 is injected to cover the surface of the wafer 200. Specifically, since the polymer material 106 is a flowable material, the polymer material 106 not only covers the side walls 200s and the upper surface 200t of the wafer 200, but also fills the top surface 208t of the first pad 208 and the release layer 104. In the space 105.

2C and 2D, the polymer material 106 is cured into a polymer substrate 108, and the polymer substrate 108 and the release layer 104 are separated. In this case, as shown in FIG. 2D, the polymer substrate 108 is turned upside down so that the top surface 208t of the first pad 208 and the top surface 210t of the second pad 210 face upward. The wafer 200 is embedded in the polymer substrate 108, and the top surface 210 t of the second pad 210 is exposed on the first surface 108 a of the polymer substrate 108. In this embodiment, the top surface 210t of the second pad 210 of the wafer 200 is coplanar with the first surface 108a of the polymer substrate 108. In one embodiment, the thickness H2 of the polymer substrate 108 may be 1 micrometer to 2000 micrometers. Compared to the thickness H2 of the polymer substrate 108, a height difference H1 of about 1 micrometer between the top surface 208t of the first pad 208 and the top surface 210t of the second pad 210 can be considered as a coplanar plane. In an alternative embodiment, the top surface 208t of the first pad 208 and the top surface 210t of the second pad 210 are both coplanar with the first surface 108a of the polymer substrate 108.

Referring to FIG. 2D and FIG. 2E, a part of the polymer substrate 108 is removed to form an opening 109. The opening 109 extends downward from the first surface 108 a of the polymer substrate 108 and exposes a top surface 208 t of the first pad 208 of the wafer 200. In one embodiment, the method for forming the opening 109 may include, but is not limited to, a lithography process and an etching process.

Please refer to FIG. 2E and FIG. 2F. Next, a screen printing step is performed to form a first circuit structure 112 on the first surface 108a of the polymer substrate 108. Specifically, the first circuit structure 112 includes conductive layers 114, 118, and 120 and an insulating layer 116. The conductive layer 114 is formed on the top surface 210 t of the second pad 210 to be electrically connected to the second pad 210. The conductive layer 118 is formed over the conductive layer 114. The insulating layer 116 is formed between the conductive layers 114 and 118 to electrically insulate the conductive layers 114 and 118. The conductive layer 120 is filled in the opening 109 and extends to cover a portion of the first surface 108 a on which the polymer substrate 108 is disposed, so as to be electrically connected to the first pad 208. In one embodiment, the conductive layer 114 and the conductive layer 120 may be sequentially formed, and the conductive layer 118 and the conductive layer 120 may be formed simultaneously. After the first circuit structure 112 is formed, the flexible substrate and the circuit structure of the embedded wafer 200 in this embodiment have been manufactured. In some embodiments, the flexible substrate and circuit structure of the embedded chip 200 can be regarded as a light emitting diode display, such as a traffic light indicator, a transparent flexible panel, a sign or an advertising sign.

3A to 3E are schematic cross-sectional views illustrating a manufacturing process of a flexible substrate and a circuit structure according to a third embodiment of the present invention.

Please refer to FIGS. 3A and 3B. The manufacturing process of the flexible substrate and circuit structure of the third embodiment is basically similar to the manufacturing process of the flexible substrate and circuit structure of the first embodiment, that is, FIG. 3A is the same as FIG. 1A and It has been described in the above paragraphs, and will not be repeated here. The manufacturing process of the flexible substrate and wiring structure of the third embodiment is described by taking the light-emitting element wafer 200 as an example. In this embodiment, the light-emitting element wafer 200 may be a horizontal light-emitting diode.

In detail, as shown in FIG. 3B, the step of disposing the wafer 200 on the release layer 104 by the transposition method includes: making the top surface 208t of the first pad 208 and the top surface 210t of the second pad 210 face away from each other. Shed layer 104. In one embodiment, the back surface 202 b of the first semiconductor layer 202 of the wafer 200 abuts or contacts the release layer 104. The above steps can be regarded as the pad-up configuration of the wafer 200 on the release layer 104.

Referring to FIG. 3C, after the wafer 200 is disposed on the release layer 104, a polymer material 106 is injected to cover a part of the sidewall 200s of the wafer 200. In one embodiment, the thickness T1 of the polymer material 106 is less than or equal to the thickness T2 of the wafer 200. In an alternative embodiment, the polymer material 106 covers at least one third of the height of the sidewall 200s of the wafer 200. That is, the thickness T1 of the polymer material 106 may be greater than or equal to one third of the thickness T2 of the wafer 200. In this case, as shown in FIG. 3C, the top surface 208 t of the first pad 208 and the top surface 210 t of the second pad 210 are exposed to the polymer material 106.

3C and 3D, the polymer material 106 is cured into a polymer substrate 108, and the polymer substrate 108 and the release layer 104 are separated. In this case, as shown in FIG. 3D, the wafer 200 is embedded in the polymer substrate 108, and the top surface 208t of the first pad 208 and the top surface 210t of the second pad 210 are exposed on the first surface 108a of the polymer substrate 108. . In one embodiment, the back surface 202 b of the first semiconductor layer 202 of the wafer 200 is coplanar with the second surface 108 b of the polymer substrate 108. In an alternative embodiment, the top surface 208 t of the first pad 208 of the wafer 200 is coplanar with the first surface 108 a of the polymer substrate 108.

Referring to FIGS. 3D and 3E, a screen printing step is performed to form a first circuit structure 212 on the first surface 108 a of the polymer substrate 108. For example, the first circuit structure 212 includes conductive layers 214, 218, 220 and an insulating layer 216. The conductive layer 214 is formed on the top surface 208 t of the first pad 208 to be electrically connected to the first pad 208. The conductive layer 218 is formed over the conductive layer 214. The insulating layer 216 is formed between the conductive layers 214 and 218 to electrically insulate the conductive layers 214 and 218. The conductive layer 220 is formed on the top surface 210 t of the second pad 210 to be electrically connected to the second pad 210. In one embodiment, the conductive layer 214 and the conductive layer 220 may be sequentially formed, and the conductive layer 218 and the conductive layer 220 may be formed simultaneously.

4 is a schematic cross-sectional view of a flexible substrate and a circuit structure according to a fourth embodiment of the present invention.

Referring to FIG. 4, the flexible substrate and circuit structure of the fourth embodiment are basically similar to the flexible substrate and circuit structure of the third embodiment. The above two are different in that the wafer 300 embedded in the flexible substrate and the circuit structure of the fourth embodiment is a vertical light emitting diode. Specifically, the light emitting element wafer 300 includes a first semiconductor layer 202, a light emitting layer 204, a second semiconductor layer 206, a first pad 208, and a second pad 210. The light emitting layer 204 is formed between the first semiconductor layer 202 and the second semiconductor layer 206. The first pad 208 is formed on the first semiconductor layer 202, a side far from the light emitting layer 204. The second pad 210 is formed on the second semiconductor layer 206 away from the other side of the light emitting layer 204. In this embodiment, the top surface 208t of the first pad 208 faces upward, and the top surface 210t of the second pad 210 faces downward.

The polymer substrate 108 surrounds the sidewall 300s of the light-emitting element wafer 300. The top surface 208t of the first pad 208 is exposed on the first surface 108a of the polymer substrate 108, and the top surface 210t of the second pad 210 is exposed on the polymer substrate 108 Of the second surface 108b. In one embodiment, the first surface 108 a and the second surface 108 b of the polymer substrate 108 are opposite to each other. Although the top surface 208t of the first pad 208 in FIG. 4 is higher than the first surface 108a of the polymer substrate 108, the present invention is not limited thereto. In other embodiments, the top surface 208t of the first pad 208 and the first surface 108a of the polymer substrate 108 may be substantially coplanar. Similarly, the top surface 210t of the second pad 210 and the second surface 108b of the polymer substrate 108 can also be substantially coplanar.

The first circuit structure 312 a is formed on the first surface 108 a of the polymer substrate 108 and is electrically connected to the first pad 208. The first circuit structure 312 b is formed on the second surface 108 b of the polymer substrate 108 and is electrically connected to the second pad 210.

Although the above embodiments only show the horizontal light-emitting diode wafer and the vertical light-emitting diode wafer, the present invention is not limited thereto. In other embodiments, the chip embedded in the flexible substrate and the circuit structure may also be a flip chip light emitting diode wafer, an active device wafer, a passive device wafer, or a combination thereof.

In summary, the present invention embeds at least one wafer into a polymer substrate by a chip first molding method. Next, a first circuit structure is formed on the first surface of the polymer substrate by a screen printing method, so that the first circuit structure is electrically connected to the first pad of at least one wafer. Therefore, the manufacturing method of the present invention can manufacture a flexible or stretchable circuit board structure, and solve the problems of wafer displacement or wafer rotation caused by unevenness of the surface or placement of the wafer, which leads to subsequent drive circuits and The problem of chip electrical connection deviation. In addition, compared with the traditional manufacturing method of the printed wiring board, the manufacturing method of the flexible substrate and the wiring structure of the present invention has the advantages of simple manufacturing process, rapid production, and low manufacturing cost, so that the product has commercial competitiveness.

Although the present invention has been disclosed as above with the examples, it is not intended to limit the present invention. Any person with ordinary knowledge in the technical field can make some modifications and retouching without departing from the spirit and scope of the present invention. The protection scope of the present invention shall be determined by the scope of the attached patent application.

100, 200, 300‧‧‧ chips

102‧‧‧ carrier

104‧‧‧ Release layer

106‧‧‧ Polymer Materials

108‧‧‧Polymer substrate

108a‧‧‧first surface

108b‧‧‧Second surface

109‧‧‧ opening

110‧‧‧Screen printing steps

112, 212, 312a‧‧‧ First Line Structure

312b‧‧‧Second Line Structure

114, 118, 120, 214, 218, 220‧‧‧ conductive layers

116, 216‧‧‧ Insulation

200s, 300s‧Sidewall of the wafer

202‧‧‧First semiconductor layer

204‧‧‧Light-emitting layer

206‧‧‧Second semiconductor layer

208‧‧‧The first pad

208t‧‧‧ Top surface of the first pad

210‧‧‧The second pad

210t‧‧‧ Top surface of the second pad

H1‧‧‧height difference

H2‧‧‧thickness of polymer substrate

T1‧‧‧thickness of polymer materials

T2‧‧‧ Wafer thickness

1A to 1E are schematic perspective views of a manufacturing process of a flexible substrate and a circuit structure according to a first embodiment of the present invention. 2A to 2F are schematic cross-sectional views illustrating a manufacturing process of a flexible substrate and a circuit structure according to a second embodiment of the present invention. 3A to 3E are schematic cross-sectional views illustrating a manufacturing process of a flexible substrate and a circuit structure according to a third embodiment of the present invention. 4 is a schematic cross-sectional view of a flexible substrate and a circuit structure according to a fourth embodiment of the present invention.

Claims (20)

A method for manufacturing a flexible substrate and a circuit structure includes: forming a release layer on a carrier; disposing at least one wafer on the release layer; injecting a polymer material to cover at least a part of a sidewall of the at least one wafer; Curing the polymer material into a polymer substrate; separating the polymer substrate and the release layer, wherein the at least one wafer is embedded in the polymer substrate, and the thickness of the polymer substrate is smaller than the thickness of the polymer substrate; A thickness of at least one wafer; and forming a first circuit structure on a first surface of the polymer substrate, the first circuit structure is electrically connected to a first pad of the at least one wafer. The method for manufacturing a flexible substrate and a circuit structure according to item 1 of the scope of patent application, wherein the at least one wafer includes a light emitting element wafer, an active element wafer, a passive element wafer, or a combination thereof. The method for manufacturing a flexible substrate and a circuit structure according to item 1 of the scope of patent application, wherein the at least one wafer includes a light-emitting element wafer, and the light-emitting element wafer includes a light-emitting diode, which includes: a first semiconductor layer; A layer formed on the first semiconductor layer; a second semiconductor layer formed on the light-emitting layer; the first pad formed on the first semiconductor layer; and a second pad formed on On the second semiconductor layer. The method for manufacturing a flexible substrate and a circuit structure according to item 3 of the scope of patent application, wherein the step of disposing the at least one wafer on the release layer includes: attaching the first connection of the at least one wafer The pad and the second pad face the release layer, and at least one of the first pad and the second pad abut against the release layer. The method for manufacturing a flexible substrate and a circuit structure according to item 3 of the scope of patent application, wherein before forming the first circuit structure on the surface of the polymer substrate, the method further includes removing a part of the polymer substrate, The first pads and the second pads of the at least one wafer are exposed. The method for manufacturing a flexible substrate and a circuit structure according to item 3 of the scope of patent application, wherein the step of disposing the at least one wafer on the release layer includes: attaching the first connection of the at least one wafer The pad and the second pad are away from the release layer. According to the method for manufacturing a flexible substrate and a circuit structure according to item 1 of the scope of patent application, in the step of injecting the polymer material, a thickness of the polymer material is less than or equal to a thickness of the at least one wafer. The method for manufacturing a flexible substrate and a circuit structure according to item 1 of the scope of patent application, wherein in the step of injecting the polymer material, the polymer material covers at least one third of a height of a sidewall of the at least one wafer. one. The method for manufacturing a flexible substrate and a circuit structure according to item 1 of the scope of the patent application, wherein the polymer material includes polydimethylsiloxane, polyurethane, thermoplastic polyurethane, polyimide, or a combination thereof. The method for manufacturing a flexible substrate and a circuit structure according to item 1 of the scope of the patent application, wherein the step of curing the polymer material into the polymer substrate includes heating to a temperature between 60 ° C and 220 ° C. The method for manufacturing a flexible substrate and a circuit structure according to item 1 of the scope of patent application, wherein a method of disposing the at least one wafer on the release layer includes a transposition method, and the transposition method includes an electrostatic method, Vacuum pick-up method, robot arm pick-and-place method, wafer-to-wafer bonding method, or stick-and-pick method. The method for manufacturing a flexible substrate and a circuit structure according to item 1 of the scope of patent application, wherein the material of the release layer includes a material having a temporary fixing property, and is used to temporarily fix the at least one wafer. The method for manufacturing a flexible substrate and a circuit structure according to item 1 of the scope of patent application, further comprising forming a second circuit structure on a second surface of the polymer substrate, the second circuit structure and the at least one wafer The second pad is electrically connected, wherein the second surface of the polymer substrate is opposite to the first surface of the polymer substrate. A flexible substrate and a circuit structure include: a polymer substrate having a first surface and a second surface opposite to each other; a plurality of light-emitting element wafers embedded in the polymer substrate; and a first circuit structure disposed in the polymer On the first surface of the substrate, the first pad or the second pad in each of the light-emitting element wafers is coplanar with the first surface of the polymer substrate, and the The first pad or the second pad protrudes from the first surface of the polymer substrate. The flexible substrate and circuit structure according to item 14 of the scope of patent application, wherein the light emitting element wafer includes a plurality of light emitting diodes, and each of the light emitting diodes includes: a first semiconductor layer; a second semiconductor layer; A layer between the first semiconductor layer and the second semiconductor layer; the first pad is connected to the first semiconductor layer; and the second pad is connected to the second semiconductor Layer-to-layer connection, wherein the second pad is higher than the first pad, and the top surface of the second pad is coplanar with the first surface of the polymer substrate. The flexible substrate and circuit structure according to item 14 of the scope of patent application, wherein the light-emitting element wafer includes a plurality of light-emitting diodes, and each of the light-emitting diodes includes: a first semiconductor layer; a second semiconductor layer; A layer between the first semiconductor layer and the second semiconductor layer; the first pad is connected to the first semiconductor layer; and the second pad is connected to the second semiconductor Layer-to-layer connection, wherein the second pad is higher than the first pad, and the top surface of the first pad is coplanar with the first surface of the polymer substrate. The flexible substrate and circuit structure according to item 16 of the scope of patent application, wherein a back surface of the first semiconductor layer and the first pad of each of the light-emitting diodes is opposite to a position of the polymer substrate. The second surface is coplanar. The flexible substrate and circuit structure according to item 14 of the scope of patent application, wherein the light-emitting element wafer includes a plurality of light-emitting diodes, and each of the light-emitting diodes includes: a light-emitting layer, which is located at the first semiconductor layer and the second Between semiconductor layers; the first pad is located on the first semiconductor layer and is exposed on the first surface of the polymer substrate; and the second pad is located on the second semiconductor layer And is exposed on the second surface of the polymer substrate. The flexible substrate and the circuit structure according to item 18 of the scope of the patent application, wherein a top surface of the first pad is coplanar with the first surface of the polymer substrate, and a top of the second pad is The plane is coplanar with the second surface of the polymer substrate. The flexible substrate and the circuit structure according to item 18 of the scope of the patent application, further including a second circuit structure disposed on the second surface of the polymer substrate, and the second circuit structure is in contact with the second Pads are electrically connected.