TW202121938A - Rigid-flex printed board and method for manufacturing the same - Google Patents

Abstract

A method for manufacturing a rigid-flex printed board, including the following steps: providing a flexible circuit substrate, which includes a first base material layer and a first circuit layer on the first base material layer; providing an adhesive sheet, the adhesive sheet comprising an adhesive layer; providing a single-sided flexible circuit board, which includes a second base material layer and a second circuit layer on the second base material layer; providing a rigid circuit board, which includes a third base material layer and a third circuit layer on the third base material layer, the rigid circuit board is provided with an opening; the adhesive sheet, the single-sided flexible circuit board, and the rigid circuit substrate are sequentially stacked on the flexible circuit substrate and then pressed, so that the second base material layer is exposed to the opening and the third circuit layer is away from the single-sided flexible circuit board, thereby obtaining the rigid-flex printed board. The disclosure also provides a rigid-flex printed board.

Description

Manufacturing method of rigid-flex board and rigid-flex board

This application relates to the field of circuit board manufacturing, in particular to a method for manufacturing a rigid-flex board and a rigid-flex board.

The rigid-flex board combines the flexibility of the flexible circuit board (FPC) and the durability of the rigid circuit board (PCB), which can meet the requirements of high reliability, high precision, transmission integrity, etc., and is widely used in consumer Electronics and communications and other electronic product fields, such as mobile phones, automobiles, etc.

At present, the general manufacturing method in the industry is to press the hard board and the soft board and then open the cover on the hard board to form an opening. The conventional process usually uses a laser to open the lid, which is not only cumbersome, but also has an error in the depth during the opening process, it is also prone to level deviation, and it will cause the phenomenon of glue overflow.

Therefore, it is necessary to provide a method for manufacturing a rigid-flex board, which can avoid errors and glue overflow in the traditional lid opening process, so as to solve the above-mentioned problems.

In addition, it is necessary to provide a rigid-flex board.

A method for manufacturing a rigid-flex board. The manufacturing method includes the following steps:

A flexible circuit substrate is provided, the flexible circuit substrate includes a first substrate layer and a first circuit layer that are stacked, and the first circuit layer includes a first connection pad;

Provide a bonding sheet, the bonding sheet includes a glue layer, the glue layer is provided with a plurality of first conductive pillars;

A single-sided flexible circuit board is provided, the single-sided flexible circuit board includes a second substrate layer and a second circuit layer that are stacked, the second circuit layer includes a plurality of second connection pads, and the second substrate layer Is provided with a second conductive post connected to the second connection pad;

A rigid circuit substrate is provided, the rigid circuit substrate includes a third base material layer and a third circuit layer that are stacked, the rigid circuit substrate is provided with a penetrating opening, and the third circuit layer includes a plurality of third connection pads, The third substrate layer is provided with a third conductive post connected to the third connection pad;

The adhesive sheet, the single-sided flexible circuit board, and the rigid circuit substrate are sequentially stacked on the flexible circuit substrate and then pressed together. The first conductive post is electrically connected to the first connection pad and the rigid circuit substrate. For the second connection pad, the end of the second conductive column away from the second connection pad is connected to the third conductive column, and the end of the third conductive column away from the third connection pad is connected to the The second conductive pillar makes the second substrate layer exposed to the opening and makes the third circuit layer away from the single-sided flexible circuit board, thereby obtaining the rigid-flex board.

Further, the manufacturing steps of the adhesive sheet include:

Providing an initial adhesive sheet, the initial adhesive sheet including the adhesive layer and a first peelable layer located on two opposite surfaces of the adhesive layer;

At least one through hole is formed in the initial bonding sheet, and the through hole penetrates the adhesive layer and the first peelable layer;

Filling conductive paste in the through holes, and curing the conductive paste to form the first conductive pillars;

The first peelable layer is removed, so that two opposite ends of the first conductive pillar protrude from the adhesive layer, thereby making the adhesive sheet.

Further, the manufacturing steps of the single-sided flexible circuit board include:

Providing a first copper clad laminate, the first copper clad laminate comprising a second peelable layer, the second substrate layer, and a first copper foil layer stacked in sequence;

Etching the first copper foil layer to form the second circuit layer;

At least one first blind hole is opened in the first copper clad laminate, and the first blind hole penetrates the second peelable layer and the second substrate layer;

Filling conductive paste in the first blind hole, and curing the conductive paste to form the second conductive pillar;

The second peelable layer is removed, so that the end of the second conductive pillar away from the second circuit layer protrudes from the second substrate layer, thereby manufacturing the single-sided flexible circuit board.

Further, the manufacturing steps of the rigid circuit substrate include:

Providing a second copper clad laminate, the second copper clad laminate comprising a third peelable layer, the third substrate layer, and a second copper foil layer stacked in sequence;

Etching the second copper foil layer to form the third circuit layer;

At least one second blind hole is opened in the second copper clad laminate, and the second blind hole penetrates the third peelable layer and the third substrate layer;

Filling the conductive paste in the second blind hole, and curing the conductive paste to form the third conductive pillar;

Opening the opening in a region of the second copper clad laminate other than the third circuit layer, the opening passing through the third peelable layer and the third substrate layer;

The third peelable layer is removed, so that the end of the third conductive pillar away from the third circuit layer protrudes from the third base material layer, thereby making the rigid circuit substrate.

Further, the glass transition temperature or melting temperature of the adhesive layer is less than or equal to the glass transition temperature or melting temperature of the third substrate layer.

A rigid-flexible combined board, the rigid-flexible combined board comprising:

A flexible circuit substrate, the flexible circuit substrate includes a first substrate layer and a first circuit layer on the surface of the first substrate layer, and the first circuit layer includes a first connection pad;

An adhesive sheet, the adhesive sheet includes an adhesive layer, and a plurality of first conductive posts are provided in the adhesive layer;

Single-sided flexible circuit board, the single-sided flexible circuit board includes a second substrate layer and a second circuit layer that are stacked, the second circuit layer includes a plurality of second connection pads, and the second substrate layer Provided with a second conductive post connected to the second connection pad;

A rigid circuit substrate, the rigid circuit substrate includes a third base material layer and a third circuit layer that are stacked, the rigid circuit substrate is provided with a penetrating opening, and the third circuit layer includes a plurality of third connection pads, so The third substrate layer is provided with a third conductive post connected to the third connection pad;

Wherein, the bonding sheet, the single-sided flexible circuit board, and the rigid circuit substrate are sequentially stacked on the flexible circuit substrate, and the first conductive post is electrically connected to the first connection pad and the first connection pad. Two connecting pads, the end of the second conductive pillar away from the second connecting pad is connected to the third conductive pillar, and the end of the third conductive pillar away from the third connecting pad is connected to the second Conductive pillars, the second substrate layer is exposed to the opening, and the third circuit layer is away from the single-sided flexible circuit board.

Further, the glass transition temperature or melting temperature of the adhesive layer is less than or equal to the glass transition temperature or melting temperature of the third substrate layer.

Further, the adhesive layer fills the gap between the first circuit layer and the gap between the second circuit layer, and the adhesive layer connects the flexible circuit substrate and the Single-sided flexible circuit board.

The manufacturing method of the rigid-flex board provided in the present application provides a rigid circuit substrate with openings. After pressing, the flexible and rigid board with openings can be formed without additional peelable layer and lid opening process. Increase the amount of glue overflow due to opening; flexible circuit substrates, adhesive sheets, single-sided flexible circuit boards, and rigid circuit substrates are laminated in sequence and then pressed, reducing the number of times of pressing, reducing the expansion and contraction between each layer and the displacement between layers; single No glue is arranged between the surface flexible circuit board and the rigid circuit substrate, which reduces the thickness of the rigid-flex board.

In order to be able to understand the above objectives, features and advantages of the application more clearly, the application will be described in detail below with reference to the accompanying drawings and specific implementations.

Please refer to FIG. 1, an embodiment of the present application provides a method for manufacturing a rigid-flex board 100. It includes the following steps:

Step S1: Provide a flexible circuit substrate 10.

The flexible circuit substrate 10 includes a first substrate layer 12 and a first circuit layer 14 and a fourth circuit layer 15 respectively located on two opposite surfaces of the first substrate layer 12.

The material of the first substrate layer 12 can usually be polyimide (PI), liquid crystal polymer (LCP), modified polyimide (MPI), etc. One of flexible materials. The thickness of the first substrate layer 12 is 25 μm-150 μm. In this embodiment, the material of the first substrate layer 12 is polyimide.

The thickness of the first circuit layer 14 is 4 μm-20 μm.

In this embodiment, the flexible circuit substrate 10 is provided with at least one through hole (not shown) penetrating the first circuit layer 14 and the first base material layer 12. The first circuit layer 14 includes an etched copper foil layer (not shown) formed on the first substrate layer 12 and a copper plating layer (not shown) formed on the copper foil layer. The copper plating layer is also filled in the through hole to form the via hole 17. Both the first circuit layer 14 and the second circuit layer include a plurality of first connection pads 16, and the first connection pads 16 are electrically connected through the via holes 17. The diameter of the first connection pad 16 is not less than 150 μm.

Step S2: Referring to FIGS. 2 to 5, an adhesive sheet 20 is provided. The adhesive sheet 20 includes an adhesive layer 22 and first conductive pillars 24 penetrating two opposite surfaces of the adhesive layer 22.

Specifically, the adhesive layer 22 includes at least one through hole 26 penetrating two opposite surfaces of the adhesive layer 22, and the first conductive pillar 24 is accommodated in the through hole 26.

Further, the two opposite ends of the first conductive pillar 24 protrude from the two opposite surfaces of the adhesive layer 22, which facilitates the subsequent pressing and bonding of the flexible and hard board 100, the first conductive The pillar 24 can be better electrically connected to the circuit layer, and better realize the conductive effect.

The thickness of the adhesive layer 22 is 12 μm-25 μm. The material of the adhesive layer 22 can generally be selected from one of insulating materials such as epoxy resin, polytetrafluoroethylene (PTFE), and industrialized liquid crystal polymer (LCP). Among them, the glass transition temperature Tg of epoxy resin is 120°C-160°C, the melting temperature Tm of industrialized liquid crystal polymer is 300°C-320°C, and the melting temperature Tm of polytetrafluoroethylene is 327°C.

The pore diameter of the through hole 26 is 50 μm-200 μm. The material of the first conductive pillar 24 is conductive paste. The conductive paste includes an epoxy resin and a conductive material, the epoxy resin acts as a bonding agent, the conductive material is selected from at least one of silver (Ag) or copper (Cu), and the first conductive pillar 24 It also includes at least one of additives such as nickel (Ni), tin (Sn), bismuth (Bi), and zinc (Zn). Wherein, the glass transition temperature Tg of the first conductive pillar 24 is 130°C-150°C.

The steps of making the adhesive sheet 20 are as follows:

As shown in FIG. 2, an initial bonding sheet 222 is provided, and the initial bonding sheet 222 includes the adhesive layer 22 and a first peelable layer 224 a located on two opposite surfaces of the adhesive layer 22. In this embodiment, the material of the first peelable layer 224a is polyethylene terephthalate (PET). In other embodiments, the first peelable layer 224a may also be other insulating materials that are easy to remove.

As shown in FIG. 3, at least one through hole 26 is formed on the initial bonding sheet 222, and the through hole 26 penetrates two opposite surfaces of the initial bonding sheet 222. The through hole 26 may be formed by mechanical drilling or laser drilling.

As shown in FIG. 4, the conductive paste is filled in the through hole 26, and the first conductive pillar 24 is formed after the conductive paste is cured. Wherein, two opposite ends of the first conductive pillar 24 may be flush with the surfaces of the two first peelable layers 224a away from the adhesive layer 22, respectively.

As shown in FIG. 5, the first peelable layer 224 a is removed, and two opposite ends of the first conductive pillar 24 protrude from the adhesive layer 22, thereby making the adhesive sheet 20.

Step S3: Referring to FIGS. 6 to 10, a single-sided flexible circuit board 30 is provided. The single-sided flexible circuit board 30 includes a second substrate layer 32 and a second substrate layer 32 disposed on the surface of the second substrate layer 32. In the circuit layer 34, the second substrate layer 32 is provided with at least one first blind hole 36, and the first blind hole 36 penetrates the second substrate layer 32 but does not penetrate the second circuit layer 34. That is, the second circuit layer 34 forms the bottom of the first blind hole 36, the second conductive pillar 35 is accommodated in the first blind hole 36, and the second conductive pillar 35 is far away from the second circuit. The end of the layer 34 protrudes from the second substrate layer 32.

The second substrate layer 32 serves as the base layer of the single-sided flexible circuit board 30, has flexibility and mainly supports the single-sided flexible circuit board 30. The material of the second substrate layer 32 can usually be polyimide (PI), liquid crystal polymer (LCP), modified polyimide (MPI), etc. One of flexible materials. Among them, the glass transition temperature Tg of polyimide is 250℃-350℃, the Tm of liquid crystal polymer is 300℃-320℃, and the glass transition temperature Tg of modified polyimide is 250 ℃-350℃.

In this embodiment, the material of the second substrate layer 32 is polyimide. The thickness of the second substrate layer 32 is 12 μm-25 μm.

The aperture of the first blind hole 36 is 75 μm-200 μm.

The material of the second circuit layer 34 is usually at least one selected from copper and a composite material of copper and nickel. The thickness of the second circuit layer 34 is 4 μm-20 μm.

The second circuit layer 34 includes a second connection pad 38, and the diameter of the second connection pad 38 is not less than 150 μm.

The material of the second conductive pillar 35 is conductive paste. The conductive paste includes an epoxy resin and a conductive material, the epoxy resin acts as a bonding agent, the conductive material is selected from at least one of silver (Ag) or copper (Cu), and the second conductive pillar 35 It also includes at least one of additives such as nickel (Ni), tin (Sn), bismuth (Bi), and zinc (Zn). Wherein, the glass transition temperature Tg of the second conductive pillar 35 is 130°C-150°C.

The steps of manufacturing the single-sided flexible circuit board 30 are as follows:

As shown in FIG. 6, a first copper clad laminate 322 is provided. The first copper clad laminate 322 includes a second peelable layer 224b, a second substrate layer 32, and a first copper foil layer 324a stacked in sequence.

As shown in FIG. 7, a portion of the first copper foil layer 324 a is etched to form the second circuit layer 34.

As shown in FIG. 8, at least one first blind hole 36 is opened in the first copper clad laminate 322, and the first blind hole 36 only penetrates the second peelable layer 224b and the second substrate layer 32 The first blind hole 36 does not penetrate the second circuit layer 34, that is, the second circuit layer 34 is formed at the bottom of the first blind hole 36.

As shown in FIG. 9, the first blind hole 36 is filled with the conductive paste, and the second conductive pillar 35 is formed after the conductive paste is cured. Wherein, the end of the second conductive pillar 35 away from the second circuit layer 34 may be flush with the surface of the second peelable layer 224 b away from the second base material layer 32.

As shown in FIG. 10, the second peelable layer 224b is removed, so that the end of the second conductive pillar 35 away from the second circuit layer 34 protrudes from the second substrate layer 32, thereby making The single-sided flexible circuit board 30.

Step S4: Referring to FIGS. 11 to 16, a rigid circuit substrate 40 is provided. The rigid circuit substrate 40 includes a third base material layer 42 and a third circuit layer 44 disposed on the surface of the third base material layer 42, so At least one second blind hole 46 is opened in the third substrate layer 42, and the second blind hole 46 penetrates the third circuit layer 44 but does not penetrate the third circuit layer 44. That is, the third circuit layer 44 forms the bottom of the second blind hole 46, the second blind hole 46 contains a third conductive pillar 45, and the third conductive pillar 45 is far away from the third circuit. The end of the layer 44 protrudes from the third substrate layer 42. The rigid circuit substrate 40 further includes an opening 48, and the opening 48 penetrates the rigid circuit substrate 40.

The third base material layer 42 serves as the base layer of the rigid circuit substrate 40 and mainly supports the rigid circuit substrate 40. The material of the third substrate layer 42 can generally be selected from one of polypropylene (PP) and polytetrafluoroethylene (PTFE). Among them, the glass transition temperature Tg of polypropylene is 100°C-150°C, and the melting temperature Tm of polytetrafluoroethylene is 327°C.

The thickness of the third substrate layer 42 is 25 μm-150 μm. In this embodiment, the material of the third substrate layer 42 is polypropylene.

The aperture of the second blind hole 46 is 75 μm-200 μm.

The material of the third circuit layer 44 is usually at least one selected from copper and a composite material of copper and nickel. The thickness of the third circuit layer 44 is 4 μm-20 μm.

The third circuit layer 44 includes a third connection pad 49, and the diameter of the third connection pad 49 is not less than 150 μm.

The material of the third conductive pillar 45 is conductive paste. The conductive paste includes an epoxy resin and a conductive material, the epoxy resin acts as a bonding agent, the conductive material is selected from at least one of silver (Ag) or copper (Cu), and the third conductive pillar 45 It also includes at least one of additives such as nickel (Ni), tin (Sn), bismuth (Bi), and zinc (Zn). Wherein, the glass transition temperature Tg of the third conductive pillar 45 is 130°C-150°C.

The steps of manufacturing the rigid circuit board 40 are as follows:

As shown in FIG. 11, a second copper clad laminate 422 is provided. The second copper clad laminate 422 includes a third peelable layer 224c, a third substrate layer 42, and a second copper foil layer 324b stacked in sequence.

As shown in FIG. 12, a portion of the second copper foil layer 324b is etched to form the third circuit layer 44.

As shown in FIG. 13, at least one second blind hole 46 is opened in the second copper clad laminate 422, and the second blind hole 46 only penetrates the third peelable layer 224c and the third substrate layer 42 The second blind hole 46 does not penetrate the third circuit layer 44, that is, the third circuit layer 44 is formed at the bottom of the second blind hole 46.

As shown in FIG. 14, the conductive paste is filled in the second blind hole 46, and the conductive paste is cured to form a third conductive pillar 45, wherein the third conductive pillar 45 is far away from the third circuit layer The end of 44 is flush with the surface of the third peelable layer 224c away from the third substrate layer 42.

As shown in FIG. 15, the opening 48 is opened in the area of the second copper clad laminate 422 except the third circuit layer 44, and the opening 48 penetrates the third peelable layer 224c and the third In the substrate layer 42, the opening 48 is disposed away from the second blind hole 46. The opening 48 is formed by mechanical drilling or laser drilling. In this embodiment, the opening 48 is formed by mechanical drilling.

As shown in FIG. 16, the third peelable layer 224c is removed, so that the end of the third conductive pillar 45 away from the third circuit layer 44 protrudes from the third substrate layer 42, so that the Rigid circuit board 40.

Step S5: Referring to FIG. 17, the adhesive sheet 20, the single-sided flexible circuit board 30, and the rigid circuit substrate 40 are laminated (falsely attached) on two opposite surfaces of the flexible circuit substrate 10 and pressed together to obtain the rigid and flexible circuit board. Combination board 100. Wherein, the second circuit layer 34 of the single-sided flexible circuit board 30 is disposed toward the direction of the flexible circuit substrate 10, and the second substrate layer 32 is disposed away from the direction of the flexible circuit substrate 10; the rigid circuit The third circuit layer 44 of the substrate 40 is disposed in a direction away from the flexible circuit substrate 10, and the third base material layer 42 is disposed toward the flexible circuit substrate 10.

After lamination, the opposite ends of the first conductive pillar 24 correspond to the first connection pad 16 and the second connection pad 38, respectively, and the end of the second conductive pillar 35 away from the second connection pad 38 corresponds to the The third conductive pillar 45 is described.

Specifically, in this embodiment, two rigid circuit substrates 40, one single-sided flexible circuit board 30, one bonding sheet 20, one flexible circuit substrate 10, and the other bonding sheet 20. The other single-sided flexible circuit board 30 and the other two rigid circuit substrates 40 are stacked in sequence and laminated to form the rigid-flex board 100. Wherein, after lamination, the opposite ends of the first conductive pillar 24 correspond to the first connection pad 16 and the second connection pad 38, respectively, and the end of the second conductive pillar 35 away from the second connection pad 38 corresponds to the third conductive Post 45, the third conductive post 45 of a rigid circuit substrate 40 located on the single-sided flexible circuit board 30 is far away from the third connection pad 49 and corresponds to the second conductive post 35, which is located at the other outermost post. The end of the third conductive pillar 45 of the rigid circuit substrate 40 away from the third connection pad 49 corresponds to the third connection pad 49 of the other rigid circuit substrate 40.

Wherein, the adhesive layer 22 of the adhesive sheet 20 may be in a semi-cured state. After pressing, the adhesive layer 22 of the adhesive sheet 20 on the side of the first circuit layer 14 is also filled in the gap between the first circuit layer 14 and the second circuit layer 34, and connects all The flexible circuit substrate 10 and the single-sided flexible circuit board 30 located on one side of the first circuit layer 14. The adhesive layer 22 of the adhesive sheet 20 on the side of the fourth circuit layer 15 is also filled in the gap between the fourth circuit layer 15 and the second circuit layer 34, and is connected to the flexible circuit substrate 10 And the single-sided flexible circuit board 30 on one side of the fourth circuit layer 15.

Moreover, the rigid circuit substrate 40 is not provided with an additional glue layer. After pressing, part of the second base material layer 32 of the single-sided flexible circuit board 30 is directly embedded in the rigid circuit substrate 40 to connect the The single-sided flexible circuit board 30 and the rigid circuit board 40 are described. The remaining part of the second substrate layer 32 is exposed through the opening 48 of the rigid circuit substrate 40 and serves as a covering layer of the rigid-flex board 100.

Moreover, after pressing, the opposite ends of the first conductive post 24 are respectively connected to the first connection pad 16 and the second connection pad 38, and the end of the second conductive post 35 away from the second connection pad 38 is connected to the The third conductive pillar 45, the third conductive pillar 45 of a rigid circuit substrate 40 located on the single-sided flexible circuit board 30, is connected to the second conductive pillar 35 at an end away from the third connection pad 49, and is located at the most The end of the third conductive pillar 45 of the other rigid circuit substrate 40 on the outer side away from the third connection pad 49 is connected to the third connection pad 49 of the other rigid circuit substrate 40.

Since the third conductive pillars 45 are provided on the rigid circuit substrate 40 and the second conductive pillars 35 are provided on the single-sided flexible circuit board 30, the first blind holes 36 and the second blind holes can be appropriately reduced. The size of the hole 46, the second connection pad 38 and the third connection pad 49.

Further, in the selection of materials for the third substrate layer 42 and the adhesive layer 22, the following conditions must be met: the glass transition temperature Tg or the melting temperature Tm of the adhesive layer 22 is less than or equal to that of the third substrate layer 42 Glass transition temperature Tg or melting temperature Tm.

In other embodiments, the structure of the flexible circuit substrate 10 is not limited to that shown in FIG. 17. For example, the number of the flexible circuit substrate 10 in the rigid-flex board 100 may be at least two. For another example, as shown in FIG. 18, the number of conductive circuit layers of the flexible circuit substrate 10 is not limited to two layers, and may also be multiple layers. The multiple conductive circuit layers can be connected by copper paste.

Please refer to FIG. 17 again. The embodiment of the present application also provides a rigid-flex board 100. The rigid-flex board 100 includes a flexible circuit substrate 10, an adhesive sheet 20, a single-sided flexible circuit board 30 and Rigid circuit board 40. The second circuit layer 34 of the single-sided flexible circuit board 30 is arranged inward, and the second substrate layer 32 is arranged outward; the third circuit layer 44 of the rigid circuit substrate 40 is arranged outward, and the third The base layer 42 is arranged inward.

The opposite ends of the first conductive pillar 24 correspond to the first connection pad 16 and the second connection pad 38, respectively, and the end of the second conductive pillar 35 away from the second connection pad 38 corresponds to the third Conductive column 45.

The adhesive layer 22 of the adhesive sheet 20 on the side of the first circuit layer 14 is also filled in the gap between the first circuit layer 14 and the second circuit layer 34, and is connected to the flexible circuit substrate 10 And the single-sided flexible circuit board 30 on one side of the first circuit layer 14. The adhesive layer 22 of the adhesive sheet 20 on the side of the fourth circuit layer 15 is also filled in the gap between the fourth circuit layer 15 and the second circuit layer 34, and is connected to the flexible circuit substrate 10 And the single-sided flexible circuit board 30 on one side of the fourth circuit layer 15.

Part of the second base material layer 32 of the single-sided flexible circuit board 30 is directly embedded in the rigid circuit substrate 40 to connect the single-sided flexible circuit board 30 and the rigid circuit substrate 40. The remaining part of the second substrate layer 32 is exposed through the opening 48 of the rigid circuit substrate 40 and serves as a covering layer of the rigid-flex board 100.

The opposite ends of the first conductive pillar 24 are respectively connected to the first connection pad 16 and the second connection pad 38, and the end of the second conductive pillar 35 away from the second connection pad 38 is connected to the third conductive pillar 45. The third conductive pillar 45 of a rigid circuit substrate 40 located on the single-sided flexible circuit board 30 is connected to the second conductive pillar 35 at an end away from the third connection pad 49, and the other is located on the outermost side. The end of the third conductive pillar 45 of the rigid circuit substrate 40 away from the third connection pad 49 is connected to the third connection pad 49 of the other rigid circuit substrate 40.

In other embodiments, the number of the flexible circuit substrate 10 in the rigid-flex board 100 may also be at least two.

Please refer to FIG. 18 again. In another embodiment of the present application, the number of conductive circuit layers of the flexible circuit substrate 10 is not limited to two layers, and may also be multiple layers. The multiple conductive circuit layers can be connected by copper paste.

The manufacturing method of the rigid-flex board 100 provided in the present application provides a rigid circuit substrate 40 with an opening 48. After pressing, there is no need to attach a peelable layer and an opening process to form a rigid-flex board with an opening 48. At the same time, it can also reduce the amount of glue overflow caused by opening the cover; the flexible circuit substrate 10, the bonding sheet 20, the single-sided flexible circuit board 30 and the rigid circuit substrate 40 are laminated in sequence and then pressed, reducing the number of pressing and reducing the number of layers between the layers. There is no glue between the single-sided flexible circuit board 30 and the rigid circuit substrate 40, which reduces the thickness of the rigid-flex board 100.

The above embodiments are only used to illustrate the technical solutions of the application and not to limit them. Although the application has been described in detail with reference to the above preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the application can be modified or equivalently replaced None should deviate from the spirit and scope of the technical solution of this application.

100: soft and hard board 10: Flexible circuit substrate 12: The first substrate layer 14: The first circuit layer 15: The fourth circuit layer 16: first connection pad 17: Via 20: Adhesive sheet 22: Glue layer 24: The first conductive pillar 26: Through hole 222: Initial bonding piece 224a: The first peelable layer 224b: second peelable layer 224c: The third peelable layer 30: Single-sided flexible circuit board 32: The second substrate layer 34: second circuit layer 35: second conductive pillar 36: The first blind hole 38: second connecting pad 322: The first copper clad laminate 324a: The first copper foil layer 324b: The second copper foil layer 40: rigid circuit board 42: The third substrate layer 44: third circuit layer 45: third conductive pillar 46: second blind hole 48: opening 49: third connection pad 422: second copper clad laminate

FIG. 1 is a schematic cross-sectional view of a flexible circuit substrate provided by an embodiment of the application. 2 is a schematic cross-sectional view of an initial bonding sheet provided by an embodiment of the application. 3 is a schematic cross-sectional view of the initial bonding sheet shown in FIG. 2 after opening a through hole. 4 is a schematic cross-sectional view of filling the first conductive pillar in the through hole shown in FIG. 3. Fig. 5 is a schematic cross-sectional view of the adhesive sheet obtained in Fig. 4 after the first peelable layer is removed. FIG. 6 is a schematic cross-sectional view of a first copper clad laminate provided by an embodiment of the application. FIG. 7 is a schematic cross-sectional view of forming a second circuit layer on the first copper clad laminate shown in FIG. 6. FIG. 8 is a schematic cross-sectional view of the first blind hole provided in the first copper clad laminate shown in FIG. 7. FIG. 9 is a schematic cross-sectional view of filling a second conductive pillar in the first blind hole shown in FIG. 8. 10 is a schematic cross-sectional view of the single-sided flexible circuit board obtained by removing the second peelable layer in FIG. 9. FIG. 11 is a schematic cross-sectional view of a second copper clad laminate provided by an embodiment of the application. FIG. 12 is a schematic cross-sectional view of forming a third circuit layer on the second copper clad laminate shown in FIG. 11. FIG. 13 is a schematic cross-sectional view of a second blind hole provided in the second copper clad laminate shown in FIG. 12. FIG. 14 is a schematic cross-sectional view of filling a third conductive pillar in the second blind hole shown in FIG. 13. FIG. 15 is a schematic cross-sectional view after the opening is formed in the diagram shown in FIG. 14. 16 is a schematic cross-sectional view of the rigid circuit substrate obtained by removing the third peelable layer in FIG. 15. 17 is a schematic cross-sectional view of the flexible circuit board shown in FIG. 1, the adhesive sheet shown in FIG. 5, the single-sided flexible circuit board shown in FIG. 10, and the rigid circuit board shown in FIG. 16. . FIG. 18 is a schematic cross-sectional view of a rigid-flex board provided by another embodiment of the application.

no.

100: soft and hard board

10: Flexible circuit substrate

12: The first substrate layer

14: The first circuit layer

15: The fourth circuit layer

16: first connection pad

20: Adhesive sheet

22: Glue layer

24: The first conductive pillar

30: Single-sided flexible circuit board

32: The second substrate layer

34: second circuit layer

35: second conductive pillar

38: second connecting pad

40: rigid circuit board

42: The third substrate layer

44: third circuit layer

45: third conductive pillar

48: opening

49: third connection pad

Claims (8)

A method for manufacturing a rigid-flex board. The improvement is that the manufacturing method includes the following steps: A flexible circuit substrate is provided, the flexible circuit substrate includes a first substrate layer and a first circuit layer that are stacked, and the first circuit layer includes a first connection pad; Provide a bonding sheet, the bonding sheet includes a glue layer, the glue layer is provided with a plurality of first conductive pillars; A single-sided flexible circuit board is provided, the single-sided flexible circuit board includes a second substrate layer and a second circuit layer that are stacked, the second circuit layer includes a plurality of second connection pads, and the second substrate layer Is provided with a second conductive post connected to the second connection pad; A rigid circuit substrate is provided, the rigid circuit substrate includes a third base material layer and a third circuit layer that are stacked, the rigid circuit substrate is provided with a penetrating opening, and the third circuit layer includes a plurality of third connection pads, The third substrate layer is provided with a third conductive pillar connected to the third connection pad; and The adhesive sheet, the single-sided flexible circuit board, and the rigid circuit substrate are sequentially stacked on the flexible circuit substrate and then pressed together. The first conductive post is electrically connected to the first connection pad and the rigid circuit substrate. For the second connection pad, the end of the second conductive column away from the second connection pad is connected to the third conductive column, and the end of the third conductive column away from the third connection pad is connected to the The second conductive pillar makes the second substrate layer exposed to the opening and makes the third circuit layer away from the single-sided flexible circuit board, thereby obtaining the rigid-flex board. The manufacturing method of the rigid-flex board as described in item 1 of the scope of patent application, wherein the manufacturing steps of the bonding sheet include: Providing an initial adhesive sheet, the initial adhesive sheet including the adhesive layer and a first peelable layer located on two opposite surfaces of the adhesive layer; At least one through hole is formed in the initial bonding sheet, and the through hole penetrates the adhesive layer and the first peelable layer; Filling conductive paste in the through holes, and curing the conductive paste to form the first conductive pillars; and The first peelable layer is removed, so that two opposite ends of the first conductive pillar protrude from the adhesive layer, thereby making the adhesive sheet. The manufacturing method of the rigid-flex board as described in item 1 of the scope of patent application, wherein the manufacturing steps of the single-sided flexible circuit board include: Providing a first copper clad laminate, the first copper clad laminate comprising a second peelable layer, the second substrate layer, and a first copper foil layer stacked in sequence; Etching the first copper foil layer to form the second circuit layer; At least one first blind hole is opened in the first copper clad laminate, and the first blind hole penetrates the second peelable layer and the second substrate layer; Filling conductive paste in the first blind hole, and curing the conductive paste to form the second conductive pillar; and The second peelable layer is removed, so that the end of the second conductive pillar away from the second circuit layer protrudes from the second substrate layer, thereby manufacturing the single-sided flexible circuit board. According to the method for manufacturing a rigid-flex board as described in item 1 of the scope of patent application, the manufacturing steps of the rigid circuit board include: Providing a second copper clad laminate, the second copper clad laminate comprising a third peelable layer, the third substrate layer, and a second copper foil layer stacked in sequence; Etching the second copper foil layer to form the third circuit layer; At least one second blind hole is opened in the second copper clad laminate, and the second blind hole penetrates the third peelable layer and the third substrate layer; Filling the conductive paste in the second blind hole, and curing the conductive paste to form the third conductive pillar; Opening the opening in a region of the second copper clad laminate other than the third circuit layer, the opening passing through the third peelable layer and the third substrate layer; and The third peelable layer is removed, so that the end of the third conductive pillar away from the third circuit layer protrudes from the third base material layer, thereby making the rigid circuit substrate. According to the manufacturing method of the rigid-flex board described in the first item of the patent application, the glass transition temperature or melting temperature of the adhesive layer is less than or equal to the glass transition temperature or melting temperature of the third substrate layer. A rigid-flex board, which is improved in that: the rigid-flex board includes: A flexible circuit substrate, the flexible circuit substrate includes a first substrate layer and a first circuit layer on the surface of the first substrate layer, and the first circuit layer includes a first connection pad; An adhesive sheet, the adhesive sheet includes an adhesive layer, and a plurality of first conductive posts are provided in the adhesive layer; Single-sided flexible circuit board, the single-sided flexible circuit board includes a second substrate layer and a second circuit layer that are stacked, the second circuit layer includes a plurality of second connection pads, and the second substrate layer Provided with a second conductive post connected to the second connection pad; and A rigid circuit substrate, the rigid circuit substrate includes a third base material layer and a third circuit layer that are stacked, the rigid circuit substrate is provided with a penetrating opening, and the third circuit layer includes a plurality of third connection pads, so The third substrate layer is provided with a third conductive post connected to the third connection pad; Wherein, the bonding sheet, the single-sided flexible circuit board, and the rigid circuit substrate are sequentially stacked on the flexible circuit substrate, and the first conductive post is electrically connected to the first connection pad and the first connection pad. Two connecting pads, the end of the second conductive pillar away from the second connecting pad is connected to the third conductive pillar, and the end of the third conductive pillar away from the third connecting pad is connected to the second Conductive pillars, the second substrate layer is exposed to the opening, and the third circuit layer is away from the single-sided flexible circuit board. The rigid-flex board as described in item 6 of the scope of patent application, wherein the glass transition temperature or melting temperature of the adhesive layer is less than or equal to the glass transition temperature or melting temperature of the third substrate layer. The rigid-flex board according to item 6 of the scope of patent application, wherein the adhesive layer fills the gap between the first circuit layer and the gap between the second circuit layer, and the adhesive layer is connected to the flexible circuit substrate And the single-sided flexible circuit board on one side of the first circuit layer.

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