TWI606769B - Method for manufacturing rigid-flexible printed circuit board - Google Patents

Description

Rigid-flexible bonding board manufacturing method

The present invention relates to the field of circuit board manufacturing, and in particular, to a rigid-flex board and a manufacturing method thereof.

The reinforcing sheet is attached to the flexible region as a common technical means in the field of rigid-flex bonded plates, and the purpose is to provide supporting force for the back surface of the flexible zone structure to be driven or connected, thereby avoiding deformation of the flexible zone structure and thus affecting Surface mount assembly of the product. Common reinforcing sheets generally need to strengthen the sheet making, strengthen the surface coating of the sheet and the reinforcing sheet in the flexible region of the rigid-flex board, and have technical problems such as long product cycle, low product reliability, high product cost and the like.

In view of the above, the present invention provides a rigid-flex board and a manufacturing method thereof that can solve the above technical problems.

A manufacturing method of a rigid-flex plate comprises the steps of: manufacturing a flexible circuit board, wherein the flexible circuit board is divided into a first region, a second region and a third region which are sequentially connected, wherein the third region is formed a finger insertion terminal; providing a second adhesive sheet; providing a fourth copper foil layer, the fourth copper foil layer being bonded to the flexible circuit board and the finger insertion terminal by the second adhesive sheet a second bonding sheet is in direct contact with the flexible circuit board; the fourth copper foil layer is formed to form a fourth conductive circuit layer, the fourth conductive circuit layer includes a conductive line corresponding to the first region; a second adhesive sheet in the second region, wherein the rigid flexible bonding plate is obtained; wherein the first region corresponds to a rigid region of the rigid flexible bonding plate, and the second region corresponds to flexibility of the rigid flexible bonding plate a third region corresponding to the finger region of the rigid-flex plate; the second adhesive sheet in the third region is used to reinforce the finger region.

A rigid flexible bonding board comprising an inner flexible circuit board, a second adhesive sheet formed on one side of the flexible circuit board, and a fourth conductive layer formed on the second adhesive sheet a circuit layer, the second bonding sheet is in direct contact with the flexible circuit board, and the rigid flexible bonding board is divided into a rigid region, a flexible region and a finger region which are sequentially connected, and the flexible circuit board is formed in the finger region There is a finger insertion terminal, and the second adhesive sheet is formed only in the rigid region and the finger region, and the second adhesive sheet of the finger region is used for reinforcing the finger region.

The rigid-flex board and the manufacturing method thereof provide the second adhesive sheet in the finger area in the production of the rigid-flex board, instead of the reinforcing sheet in the prior art, and the whole process of the reinforcing sheet is omitted. The manpower and material resources are saved, thereby reducing the cost; shortening the cycle of the related products; since the rigid-flex plate provided by the invention does not need to be subjected to the high-temperature heat treatment process of the reinforcing sheet pressing, the gold surface welding and soldering ability can be avoided. The impact has increased the reliability of the product.

10‧‧‧Flexible substrate

11‧‧‧Flexible insulation

12‧‧‧First copper foil

13‧‧‧Second copper foil

100‧‧‧Flexible circuit board

110‧‧‧First area

120‧‧‧Second area

130‧‧‧ Third Area

21‧‧‧First conductive circuit layer

22‧‧‧Second conductive circuit layer

23‧‧‧First cover layer

24‧‧‧second cover layer

25‧‧‧ first opening

26‧‧‧Finger terminal

31‧‧‧The first peelable glue

32‧‧‧Separable peelable glue

41‧‧‧First adhesive sheet

411‧‧‧ first through slot

42‧‧‧Second bonding sheet

421‧‧‧Second pass

422‧‧‧3rd slot

51‧‧‧ Third copper foil

52‧‧‧fourth copper foil

200‧‧‧ circuit substrate

53‧‧‧ conductive through holes

531‧‧‧through hole

532‧‧‧First conductive copper layer

61‧‧‧ Third conductive circuit layer

62‧‧‧fourth conductive layer

71‧‧‧First solder mask

711‧‧‧First solder mask opening

712‧‧‧Second electrical contact pads

72‧‧‧Second solder mask

721‧‧‧Second solder mask opening

722‧‧‧ Third electrical contact pad

81‧‧‧First gold plating

82‧‧‧Second gold plating

83‧‧‧ third gold plating

300‧‧‧ rigid-flex board

310‧‧‧Rigid area

320‧‧‧Flexible zone

330‧‧‧ finger zone

1 is a cross-sectional view showing a flexible circuit board according to an embodiment of the present invention.

Fig. 2 is a cross-sectional view showing the copper foil on both sides of the flexible circuit board shown in Fig. 1 formed into a conductive wiring layer.

Figure 3 is a cross-sectional view showing a flexible circuit board formed by pressing a cover film on both sides of the conductive wiring layer shown in Figure 2.

Figure 4 is a cross-sectional view of the cover film shown in Figure 3 after it has been peeled off.

FIG. 5 is a cross-sectional view showing a cut sheet and a copper foil after cutting according to an embodiment of the present invention.

Fig. 6 is a cross-sectional view showing a circuit board formed by pressing a bonding sheet and a copper foil on both sides of the flexible circuit board shown in Fig. 4.

Fig. 7 is a cross-sectional view showing the circuit board shown in Fig. 6 after a through hole is formed.

Fig. 8 is a cross-sectional view showing the through hole of Fig. 7 after copper plating to form a conductive via.

Fig. 9 is a cross-sectional view showing the copper foil shown in Fig. 8 formed into a conductive wiring layer.

Figure 10 is a cross-sectional view showing the solder resist layer formed on the conductive wiring layer shown in Figure 9.

Figure 11 is a cross-sectional view showing the rigid-flex board formed after removing the peelable glue on the circuit substrate shown in Figure 10.

Figure 12 is a cross-sectional view showing the surface of the rigid-flex plate shown in Figure 11 after surface treatment.

A rigid-flex plate and a manufacturing method thereof according to the present invention will be further described below with reference to FIGS. 1 to 12 and embodiments.

A method of fabricating a rigid-flex plate 300 includes the following steps: First, referring to FIG. 1, a flexible substrate 10 is provided.

The flexible substrate 10 can be a single panel or a double panel. The following steps are all described by taking a double panel structure as an example.

The flexible substrate 10 includes a flexible insulating layer 11 and a first copper foil 12 and a second copper foil 13 formed on opposite sides of the flexible insulating layer 11.

The flexible insulating layer 11 may be a flexible insulating material such as polyimide, polyethylene or polycarbonate.

In the second step, referring to FIG. 2, the first copper foil 12 and the second copper foil 13 are formed into a first conductive wiring layer 21 and a second conductive wiring layer 22.

The first conductive circuit layer 21 and the second conductive circuit layer 22 can be formed by an image transfer process and an etching process.

In the third step, referring to FIG. 3, a first cover film layer 23 is pressed on the surface of the first conductive circuit layer 21 away from the flexible insulating layer 11, and the second conductive circuit layer 22 is away from the second conductive circuit layer 22 A second cover film layer 24 is press-bonded onto the surface of the flexible insulating layer 11, thereby forming a flexible circuit board 100.

The flexible circuit board 100 is artificially divided into three regions, which are a first region 110, a second region 120, and a third region 130. The first region 110, the second region 120, and the third region 130 are sequentially connected. The first region 110 corresponds to the rigid region 310 of the finally formed rigid flexible bonding plate 300, which corresponds to the flexible region 320 of the finally formed rigid flexible bonding plate 300, the third region 130 corresponding to the final The formed rigid flexure bonds the finger area 330 of the panel 300.

The first cover film layer 23 is formed with a first opening 25. The first opening 25 is located in the third region 130. The first conductive circuit layer 21 exposed from the first opening 25 is defined as a finger insertion terminal 26. The finger insertion terminal 26 is for connecting electronic components.

In the fourth step, referring to FIG. 4, a first peelable adhesive 31 is pressed onto the first cover film layer 23, and a second peelable adhesive 32 is pressed onto the second cover film layer 24.

The first peelable adhesive 31 is located in the second region 120 and the third region 130 , and the second peelable adhesive 32 is located only in the second region 120 .

The fifth step, please refer to FIG. 5-6, providing a third copper foil 51, a fourth copper foil 52, a first bonding sheet 41 and a second bonding sheet 42, the third copper foil 51 and the first The four copper foils 52 are respectively bonded to the opposite sides of the flexible circuit board 100 after being bonded to the peelable adhesive by the first adhesive sheet 41 and the second adhesive sheet 42 to form a circuit substrate 200.

Referring to FIG. 5 , a first through slot 411 is formed at a boundary between the second region 120 and the first region 110 of the first adhesive sheet 41 , and the first region 110 and the second region of the second adhesive sheet 42 . A second through slot 421 and a third through slot 422 are respectively formed at the junction of the junction of the second region 120 and the third region 130. The first through groove 411, the second through groove 421, and the third through groove 422 may be formed by mechanical cutting or laser cutting.

The first through slot 411, the second through slot 421, and the third through slot 422 each have a certain width. In this embodiment, the first through slot 411, the second through slot 421, and the third The through slots 422 all fall into the second region 120. In other embodiments, the first through slot 411 and the second through slot 421 may also be located in the first region 110 , and the third through slot 422 may also be located in the third region 130 .

Referring to FIG. 6, the second adhesive sheet 42 located in the third region 130 is in direct contact with the second cover film layer 24 of the flexible circuit board 100. The direct contact here refers to two mediums in direct contact. There is no third medium between them.

The material of the first adhesive sheet 41 and the second adhesive sheet 42 may be enhanced by a fiberglass cloth base, a paper base, a composite base, an aromatic amine fiber nonwoven fabric base or a synthetic fiber based epoxy resin, a phenolic resin, etc. A prepreg of the material.

In the sixth step, referring to FIGS. 7-8, at least one conductive via 53 is formed at a position corresponding to the first region 110 of the circuit substrate 200.

Specifically, referring to FIG. 7 , at least one through hole 531 is formed at a position corresponding to the first region 110 of the circuit substrate 200 by mechanical drilling or laser drilling, and the through hole 531 penetrates the third copper. The foil 51, the first adhesive sheet 41, the flexible circuit board 100, the second adhesive sheet 42, and the fourth copper foil 52.

Thereafter, referring to FIG. 8 , a first conductive copper layer 532 is formed on the inner wall of the through hole 531 by plating. The conductive via 53 is electrically connected to the third copper foil 51, the first adhesive sheet 41, and flexible The circuit board 100, the second bonding sheet 42, and the fourth copper foil 52. In addition, in other embodiments, a copper plating layer may be formed on the surfaces of the third copper foil 51 and the fourth copper foil 52 when the conductive copper layer is formed.

In the seventh step, referring to FIG. 9, the third copper foil 51 and the fourth copper foil 52 are respectively formed into a third conductive wiring layer 61 and a fourth conductive wiring layer 62.

The third conductive circuit layer 61 and the fourth conductive circuit layer 62 can be formed by an image transfer and etching process.

Specifically, the third conductive wiring layer 61 is formed only in the first region 110. The fourth conductive circuit layer 62 is formed in the first region 110 and the third region 130. The conductive via 53 electrically connects the third conductive circuit layer 61, the first conductive circuit layer 21, and the second conductive circuit. Layer 22 and the fourth conductive circuit layer 62.

In other embodiments, the fourth conductive wiring layer 62 may be formed only in the first region 110.

In the eighth step, referring to FIG. 10, a first solder resist layer 71 is formed on the surface of the third conductive circuit layer 61, and a second solder resist layer 72 is formed on the surface of the fourth conductive trace layer 62.

Specifically, the first solder resist layer 71 and the second solder resist layer 72 can be formed by printing a solder resist ink. The first solder resist layer 71 is formed with at least one first solder resist opening 711, and the second solder resist layer 72 is formed with at least one second solder resist opening 721. The first solder resist opening 711 and the second solder resist opening 721 are both located in the first region 110, and the third conductive circuit layer 61 exposed from the first solder resist opening 711 is defined as the second electrical contact. The pad 712, the fourth conductive circuit layer 62 exposed from the second solder resist opening 721 is a third electrical contact pad 722.

In the ninth step, referring to FIG. 11, the first peelable glue 31 and the second peelable glue 32 are removed.

Specifically, the first adhesive sheet 41 located in the second region 120 and the third region 130 and the second adhesive sheet 42 located in the second region 120 are respectively associated with the first peelable rubber 31 and the first adhesive strip 31 The second peelable adhesive 32 is bonded together, and the first adhesive sheet 41 and the second adhesive sheet 42 have the first through groove 411, the second through groove 421 and the third through groove 422. Cutting the first adhesive sheet 41 and the second adhesive sheet 42 along the first through slot 411, the second through slot 421 and the third through slot 422, and removing the first peelable adhesive 31 and the second removable Stripping the adhesive 32, and removing the first adhesive sheet 41 located in the second region 120 and the third region 130 and the second adhesive sheet 42 located in the second region 120, that is, The first cover film layer 23, the finger insertion terminal 26, and the second cover film layer 24 located in the second region 120 may be exposed in the second region 120 and the third region 130.

In other embodiments, the method of removing the first adhesive sheet 41 located in the second region 120 and the third region 130 and the second adhesive sheet 42 located in the second region 120 is not limited to use. Stripping can also be directly removed by laser etching or the like.

Referring to FIG. 12, a first gold plating layer 81, a second gold plating layer 82, and a third surface are formed on the surfaces of the finger insertion terminal 26, the second electrical contact pad 712, and the third electrical contact pad 722, respectively. The gold plating layer 83 is further obtained to obtain the rigid flexible bonding plate 300.

In other embodiments, the second gold plating layer 82 and the third gold plating layer 83 may also be a silver plating layer or an organic solder resist layer.

Referring to FIG. 12 , the rigid flexible board 300 includes a flexible circuit board 100 , and a first adhesive sheet 41 and a second adhesive sheet 42 respectively formed on opposite sides of the flexible circuit board 100 . a third conductive circuit layer 61 on the surface of the first adhesive sheet 41, a fourth conductive circuit layer 62 formed on the surface of the second adhesive sheet 42, and one of the surfaces formed on the surface of the third conductive circuit layer 61. The solder resist layer 71 is formed on the surface of the fourth conductive wiring layer 62 as a second solder resist layer 72 and at least one conductive via 53. The first adhesive sheet 41 and the second adhesive sheet 42 are in direct contact with the flexible circuit board 100. The rigid flexible joint plate 300 is divided into a rigid region 310, a flexible region 320 and a finger region 330. The rigid region 310 The flexible area 320 and the finger area 330 are sequentially connected. The second adhesive sheet 42 is located in the rigid region 310 and the finger region 330. The first adhesive sheet 41, the third conductive circuit layer 61 and the fourth conductive circuit layer 62 are all located in the rigid region 310.

The flexible circuit board 100 includes a flexible insulating layer 11 , a first conductive circuit layer 21 and a second conductive circuit layer 22 formed on opposite surfaces of the flexible insulating layer 11 . A first cover film layer 23 on the surface of the first conductive circuit layer 21 and a second cover film layer 24 formed on the surface of the second conductive circuit layer 22. The first adhesive sheet 41 is in contact with the first first cover film layer 23, and the second adhesive sheet 42 is in contact with the second cover film layer 24. The first conductive circuit layer 21 includes a finger insertion terminal 26 that is located within the finger area 330. The first cover film layer 23 includes a first opening 25 located in the finger area 330, and the finger insertion terminal 26 is exposed from the first opening 25.

The first solder resist layer 71 is formed on the surface of the third conductive wiring layer 61, and the second solder resist layer 72 is formed on the surface of the fourth conductive wiring layer 62. The first solder resist layer 71 includes at least one first solder resist opening 711 , and the second solder resist layer 72 includes at least one second solder resist opening 721 . The first solder resist opening 711 and the second solder resist opening 721 are both located in the rigid region 310, and the third conductive circuit layer 61 exposed from the first solder resist opening 711 is defined as a second electrical contact pad. 712. The fourth conductive circuit layer 62 exposed from the second solder resist opening 721 is a third electrical contact pad 722. The surfaces of the finger insertion terminal 26, the second electrical contact pad 712 and the third electrical contact pad 722 are respectively formed with a first gold plating layer 81, a second gold plating layer 82 and a third gold plating layer 83, and the second electrical contact The pad 712 and the third electrical contact pad 722 are used for external electronic components.

The conductive via 53 is located in the rigid region 310. The conductive via 53 electrically connects the third conductive trace layer 61, the first conductive trace layer 21, the second conductive trace layer 22, and the fourth conductive trace layer 62. .

The rigid-flex board and the manufacturing method thereof provide the second adhesive sheet in the third region when the rigid-flex board is produced, and can function as a reinforcing sheet in the prior art; The flexible region and the finger region of the flexible bonding plate are added with peelable glue, which is convenient for removing the adhesive sheet; compared with the prior art, the rigid flexible bonding plate provided by the invention and the manufacturing method thereof omits the purity for bonding the reinforcing sheet The rubber layer has a thinner and lighter finger area; since the reinforcing sheet is not required to be attached, the production and bonding process of the reinforcing sheet is omitted, thereby saving human resources; and at the same time, the pressing reinforcing sheet is omitted. In the process, there is no need to add additional consumables such as silicone pads, which saves cost; in addition, since the reinforcing sheet pressing process is omitted, the high-temperature heat treatment process of the reinforcing sheet pressing is omitted, and the gold surface bonding and soldering can be avoided. The capability is affected, and the reliability of the product is improved; because the process is omitted, the rigid-flex board and the manufacturing method thereof provided by the invention not only reduce the cost, but also shorten the cycle of related products, The competitiveness of products.

In summary, the present invention complies with the requirements of the invention patent and submits a patent application according to law. The above description is only the preferred embodiment of the present invention, and equivalent modifications or variations made by those skilled in the art will be included in the following claims.

11‧‧‧Flexible insulation

21‧‧‧First conductive circuit layer

22‧‧‧Second conductive circuit layer

23‧‧‧First cover layer

24‧‧‧second cover layer

25‧‧‧ first opening

26‧‧‧Finger terminal

41‧‧‧First adhesive sheet

42‧‧‧Second bonding sheet

53‧‧‧ conductive through holes

61‧‧‧ Third conductive circuit layer

62‧‧‧fourth conductive layer

71‧‧‧First solder mask

711‧‧‧First solder mask opening

712‧‧‧Second electrical contact pads

72‧‧‧Second solder mask

721‧‧‧Second solder mask opening

722‧‧‧ Third electrical contact pad

81‧‧‧First gold plating

82‧‧‧Second gold plating

83‧‧‧ third gold plating

300‧‧‧ rigid-flex board

310‧‧‧Rigid area

320‧‧‧Flexible zone

330‧‧‧ finger zone

Claims (4)

A manufacturing method of a rigid-flex plate comprises the steps of: manufacturing a flexible circuit board, wherein the flexible circuit board is divided into a first region, a second region and a third region which are sequentially connected, wherein the third region is formed a finger insertion terminal; providing a second adhesive sheet; providing a fourth copper foil layer, the fourth copper foil layer being bonded to the flexible circuit board and the finger insertion terminal by the second adhesive sheet a second bonding sheet is in direct contact with the flexible circuit board; the fourth copper foil layer is formed to form a fourth conductive circuit layer, the fourth conductive circuit layer includes a conductive line corresponding to the first region; a second adhesive sheet in the second region, wherein the rigid flexible bonding plate is obtained; wherein the first region corresponds to a rigid region of the rigid flexible bonding plate, and the second region corresponds to flexibility of the rigid flexible bonding plate a third region corresponding to the finger region of the rigid-flex plate; the second adhesive sheet in the third region is used to reinforce the finger region. The method for fabricating a rigid flexible board according to claim 1, wherein the method for fabricating the flexible circuit board comprises the steps of: providing a flexible substrate, the circuit substrate comprising a flexible insulating layer; Forming a first copper foil layer and a second copper foil layer on opposite surfaces of the flexible insulating layer; respectively forming the first copper foil and the second copper foil to form a first conductive circuit layer and a second conductive circuit layer; a first cover film layer is formed on a surface of the first conductive circuit layer away from the flexible insulating layer, and is formed on a surface of the second conductive circuit layer away from the flexible insulating layer A second cover film layer, thereby forming a flexible circuit board. The method for fabricating a rigid-flex board according to claim 2, wherein the first cover film layer is formed with a first opening, the first opening is located in the third area, and the finger insertion terminal is from the first Exposed in the opening. The method of manufacturing the rigid-flex board according to claim 1, wherein, when the second bonding sheet is provided, the method further includes the steps of: providing a first bonding sheet, and forming the first bonding sheet The other side of the flexible circuit board opposite to the second adhesive sheet; providing a fourth copper foil layer further comprising the steps of: providing a third copper foil and bonding the third copper foil to the first A sticky piece on the piece.