TWI359734B - Stiffener and flexible printed circuit board with - Google Patents

Description

1359734 100 years. December oi 梭 正 替换 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 六 六 六 六 六 六 六 六board. [Prior Art] [0002] With the continuous development of foldable electronic products such as a folding mobile phone and a slide mobile phone, a flexible printed circuit board (Flexible Printed Circuit Board) with light, thin, short, small, and bendable characteristics is available. FPCB) is widely used in electronic products to achieve electrical connections between different circuits. In order to obtain FPCB with better flexing performance, it has become a research hotspot to improve the flexural properties of the base film materials used in FPCB. See the literature Electrical Insulation Maganize, Volume 5, Issue 1, Jan.-Feb., 1 989 Papers: 15-23, “Ap-pl cations of Polyimide Filins to the Elec-trical and Electronic Industries in Japan” O , [ 0003] In order to meet the design requirements for the versatility of foldable electronic products, the number of electronic components mounted on the surface of the FPCB has also increased accordingly. However, FPCBs with good flexural properties compared to rigid boards have low mechanical strength, low load carrying capacity, and are easy to use during installation, such as mounting electronic devices in Surface Mount Technology (SMT). Cracked or damaged, unable to carry large mass or multiple electronic devices, hindering the development of multi-functional folding products. At present, as shown in FIG. 1 , the reinforcing sheet 110 made of polyimide (PI) material is generally pressed by an adhesive layer 120 made of epoxy resin to soft 097100308. Form No. A0101 No. 4 Page / A total of 17 pages 1003448511-0 1359734 100 years of December 0 lack of nuclear positive #Si page substrate 130 surface, to make a high load carrying capacity of the reinforcing FPCB10. However, PI differs from the coefficient of thermal expansion (CET) of the epoxy resin in that the pressure-sensitive adhesive layer 120 and the reinforcing sheet 110 are in the process of the flexible substrate 130, and the reinforcing sheet 110 containing the PI and the epoxy resin are included. When the adhesive layer 120 is heated, the degree of expansion and contraction of the two layers is different, which tends to cause warpage of the reinforcing FPCB10 and increase the difficulty of subsequent surface mounting of electronic components. SUMMARY OF THE INVENTION [0004] In view of the above, it is necessary to provide a reinforcing plate and a reinforcing flexible circuit board including the reinforcing plate to increase the mechanical strength of the flexible circuit board and to avoid warping of the flexible circuit board. [0005] Hereinafter, a reinforcing plate and a reinforcing flexible circuit board including the reinforcing plate will be described in the plural embodiments. [0006] The reinforcing plate is formed by alternately arranging at least one polyimine layer and at least one polyether quinone layer. The number of layers of the polyimine layer is N, the number of layers of the polyether quinone layer is Μ, N = M + 1, and the sum of N + M is greater than or equal to 3, the polyether quinone imine The layer is composed of a polyether quinone imide material, and the structural formula A of the polyether quinone imine material is:

. The polyether oxime has a thermal expansion coefficient of 16 乂 1 plant 6~18 乂 10_61 (_1. [0008] The reinforced flexible circuit board, which comprises a flexible circuit board and is attached to a flexible electric 097100308 Form No. A0101 Page 5 / A total of 17 pages 1003448511-0 1359734 100 years. December 0 lack of nuclear core for the private page board reinforcement board. The reinforcement board is formed by alternating at least one polyimide layer and at least one polyether quinone layer. The number of layers of the polyimide layer is N,

The number of layers of the polyetherimine layer is Μ and N = M+1. The polyether quinone layer is composed of a polyether quinone material, and the structural formula A of the polyether quinone material

[0009]

. The polyether oximine has a thermal expansion coefficient of 16 x 10 _ 6 to 18 x 10 _ 6 K 。 . [0010] Compared with the prior art, the reinforcing plate is made of a polyether quinone layer having the structural formula A, since the thermal expansion coefficient of the polyether quinone is similar to the thermal expansion coefficient of the polyimine, ie, polyether The expansion and contraction rates of quinone imine and polyimine are similar when heated. Therefore, the flexible circuit board including the reinforcing plate is less prone to warpage, improves structural stability, and facilitates subsequent process operations. [Embodiment] The reinforcing plate provided by the embodiment of the present technical solution and the reinforcing flexible circuit board including the reinforcing plate are further described in detail below with reference to the accompanying drawings and the embodiments. [0012] Since the actual thickness of the reinforcing plate is very thin and has the same structure along the width direction, in order to clearly show the structure of the reinforcing plate, the structure of the reinforcing plate will be described in detail below with reference to a partial cross-sectional enlarged view of the reinforcing plate (Fig. 2 ' Figure 3 and Figure 4). Similarly, the structure of the reinforcing flexible circuit board (shown in Figures 5 and 6) is also illustrated by a partial cross-sectional enlarged view for easy understanding. 097100308 Form No. A0101 Page 6 of 17 1003448511-0 1359734 _______ • 100 years. December 0·2, press the replacement page [0013] Please refer to FIG. 2, the reinforcing plate provided by the first embodiment of the present technical solution 2〇, used to fit on a flexible circuit board to improve the mechanical properties of the flexible circuit board. The reinforcing plate 20 is composed of at least one layer 210 and at least one poly-imine (

Polyetheriraide, layer 220 is alternately arranged. The number of layers of the pi layer 210 is N, and the number of layers of the PEI layer 220 is Μ. According to the different design requirements of the circuit board, the number of layers of the layer 210 and the number of layers of the layer 220 may be equal or unequal. Therefore, the opposite outermost sides of the reinforcing plate 20 may be the layer 210 at the same time, or both. The tantalum layer 220 or one side is the tantalum layer 210 and the other side is the tantalum layer 220. The reinforcing plate 20 has a thickness of 25/zm to 250" Wherein, the thickness of the PI layer 210 is 25/im~75//m, or the thickness of the PEI layer 220 is 25/zm~75/im, and the thickness of the pi layer 210 and the thickness of the PEI layer 220 can be determined according to design requirements as long as the reinforcing plate 20 is satisfied. The total thickness is 25# m~250/zm. [0014] In this embodiment, the reinforcing plate 20 is a five-layer composite reinforcing plate comprising three PI layers 210 and two PEI layers 220, namely: N=3, M=2. The PEI layer 220 is located between the two PI layers 210 for bonding the adjacent two pi layers 210 to form the reinforcing plate 20. The outermost side of the reinforcing plate 20 is a pi layer 210. The outermost PI layer 210 is for bonding to a flexible circuit board. Of course, the number of layers of the reinforcing plate 2 including the PI layer 210 and the PEI layer 220 is not limited, and may be determined according to different design requirements, as long as N = M + 1 (ie, the outermost layer is the pi layer 210). [0015] The PEI layer 220 is composed of a PEI material, and the structural formula A of the PEI material is 097100308. Form No. A0101 Page 7 of 17 1003448511-0 1359734 100 years. December 02 Pressing the positive page

[0017] The PEI material has an ether group on the molecular chain of the structural formula A. The ether group increases the flexibility of the molecular chain of the structural formula A, so that the PEI material has good flexibility. [0018] In addition, the PEI material has good fluidity in a molten state and has good adhesion, and the thermal expansion coefficient of the PEI material is 16×10_6~ΙδχΙΟ^Γ1, which is similar to the thermal expansion coefficient of the PI material. Therefore, when the reinforcing plate 20 made of the PI layer 210 is bonded by the PEI layer 220, the degree of expansion and contraction of the PEI material and the PI material tend to be uniform, and the warpage of the reinforcing plate 20 can be prevented. [0019] PEI can be 4, 4 Any one of -diaminodiphenyl ether, m-phenylenediamine or p-phenylenediamine with 2,2'-bis[4-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride It is obtained by heating polycondensation and imidization in a solution of hydrazine. Of course, PEI can also be obtained by other methods as long as the prepared PEI has the structural formula A. [0020] Please refer to FIG. 3, which is the same as the reinforcing plate 30 provided in the first embodiment of the present technical solution. The difference is that the number of layers of the PI layer 310 is The number of layers of N and PEI layer 320 is the same, that is, M = N. In this embodiment, the reinforcing plate 30 is a four-layer composite reinforcing plate comprising two PI layers 310 and two PEI layers 320, namely: M = N = 2. At this time, the opposite outermost sides of the reinforcing plate 30 are the PI layer 310 on one side, and the other side 097100308 is on the other side. Form No. A0101 Page 8 of 17 1003448511-0 1359734 .100. December Ob modified correction page It is a PEI layer 320. The outermost PI layer 310 or PEI layer 320 can be used to conform to a flexible circuit board. [0021] Please refer to FIG. 4 , which is the same as the reinforcing plate 40 provided in the first embodiment of the present technical solution. The difference is that the number of layers of the PI layer 410 is the same. The relationship between the number of layers of N and PEI layer 420 is M is M = N + 1. In this embodiment, the reinforcing plate 40 includes a PI layer 410 and two PEI layers 420 attached to opposite sides of the PI layer 410, namely: M = 2, N=1. The opposite outermost sides of the reinforcing plate 40 are simultaneously the PEI layer 420. The outermost PEI layer 420 is for bonding to a flexible circuit board.

I

[0022] Referring to FIG. 5, a flexible circuit board 50 according to a fourth embodiment of the present technical solution, including a flexible circuit board 510, is described as an example of a flexible circuit board including a reinforcing board 20 according to the first embodiment of the present technical solution. The reinforcing plate 20 and the adhesive layer 520. The flexible circuit board 510 is a single-layer or double-sided single-layer or multi-layer circuit substrate which is fabricated by a metal-clad substrate through a series of manufacturing processes, such as making a circuit, a via hole, a protective film or a plating process. . The flexible circuit board 510 has a reinforcing surface 511 for attaching to the reinforcing plate 20. [0023] The reinforcing plate 20 is adhered to the reinforcing surface 511 of the flexible circuit board 510 by the adhesive layer 520. In the present embodiment, the outermost layer of the reinforcing plate 20 is the PI layer 210. The PI layer 210 is adhered to the reinforcing surface 511 of the flexible circuit board 510 via the adhesive layer 520. [0024] The adhesive layer 520 has a thickness of 25 μm to 70 μRa. In this embodiment, the adhesive layer 520 is composed of a PEI material, and the structural formula A of the PEI material is: 097100308 Form No. A0101 Page 9 of 17 1003448511-0 1359734 [0025]

[0026] The PEI material has good fluidity in the molten state and has good cohesive force, and the thermal expansion coefficient of the PEI material is 16×10_6~18χ1 (Γ6Κ_1. Similarly, it is known that the heating is bonded by the adhesive layer 520 to the flexible circuit board 510 and the reinforcing plate. When the flexible circuit board 50 is made, the expansion and contraction of the material of the adhesive layer 520 and the material of the reinforcing plate 20 tend to be uniform, and the warpage of the reinforcing flexible circuit board 50 can be avoided. [0027] It can be understood that The reinforcing flexible circuit board 50 may also be a flexible circuit board 510 including the reinforcing board 30 provided in the second embodiment or the reinforcing board 40 provided in the third embodiment to increase the mechanical strength of the flexible circuit board 510. [0028] The reinforcing flexible circuit board 60 provided by the fifth embodiment of the present invention is similar to the structure of the reinforcing flexible circuit board, and the structure of the reinforcing flexible circuit board is similar to that of the flexible circuit board provided by the first embodiment. The difference is that the reinforcing plate 20 is directly attached to the flexible circuit board 61 to form the reinforcing flexible circuit board 60, and no adhesive is used. The reinforcing surface 611 of the flexible circuit board 61 is in contact with the reinforcing plate 20. [0029] In the present embodiment, the outermost layer of the reinforcing plate 2 is a layer of ^. Since the fluidity is good at the time of melting, it also has a bonding force, so the outermost side of the reinforcing plate 2〇 The layer 21G can function as an adhesive to bond the reinforcing plate 2() to the flexible circuit board 610. 097100308 Form No. 1010101 Page 10 of 17 1003448511-0 1359734 Add 0 years. December 0·2 Correction Replacement Page [0030] It can be understood that the reinforcing flexible circuit board 6 can also be a flexible circuit board 610 including the reinforcing plate 3 provided by the second embodiment or the reinforcing plate 4 () provided in the third embodiment to increase softness. The mechanical strength of the circuit board 610. [0031] In addition, the PEI material and the P1 material are both viscous, but the bonding force of the PEI material is better than that of the PI material. Therefore, in order to ensure that the reinforcing flexible circuit board 60 does not peel off Or layering, preferably, using the pEI material to make the outermost structure. [0032] In summary, the present invention has indeed met the requirements of the invention patent, and the patent is filed according to law. However, the above is only the present. The preferred embodiment of the invention cannot limit the application of the case The equivalent modifications or variations made by those skilled in the art to the spirit of the present invention are intended to be included in the scope of the following claims. [FIG. 1] FIG. 1 is a reinforcement provided by the prior art. [0034] FIG. 2 is a partial cross-sectional enlarged view of a reinforcing plate according to a first embodiment of the present technical solution. [0035] FIG. 3 is a partial cross-sectional enlarged view of a reinforcing plate according to a second embodiment of the present technical solution. [ Fig. 4] Fig. 4 is a partial cross-sectional enlarged view of a reinforcing plate provided by a second embodiment of the present technical solution. 5 is an enlarged view of a portion of a reinforcing flexible circuit board according to a fourth embodiment of the present technical solution. [0037] FIG. [0038] FIG. 6 is a reinforced flexible circuit board provided by the fifth embodiment of the present technical solution. 097100308 Form No. A0101 Page 11/Total Page 1003448511-0 1359734 [0040] [0041] [0042] [0043] [0048] [0048] [0048] 100 years. December 0. 2, the shuttle is replacing the enlarged view of the page section. [Main component symbol description] Reinforced FPCB : 10 Reinforced piece: 110 Adhesive layer: 120,520 Flexible substrate: 130 Reinforcing plate: 20, 30, 40 Layer: 210, 310, 410 Layer: 220, 320, 420 Reinforcement Flexible circuit board: 50, 60 Flexible circuit board: 510, 610 Reinforcement surface: 511, 611 097100308 Form number Α 0101 Page 12 / Total 17 pages 1003448511-0

Claims (1)

1359734 • 100 years. December revision _^ page VII, the scope of application for patents: 1, a reinforced plate' improvement is that it is formed by alternately arranging at least one layer of polyimine and at least one layer of amylin The number of layers of the polyimine layer is N 'the number of layers of the polyimine layer is Μ, and n = M + 1, N = M or M = N+1, and the sum of N + M Greater than or equal to 3, the polyether quinone imine layer is composed of a polyether quinone imine material, and the structural formula of the polyether quinone imine material is: 'The thermal expansion coefficient of the polyether oxime imine is 16 χ 10 _ 6 ~ 18 χ 10 -6 κ - ι 〇 如 如 如 如 如 如 如 如 如 如 如 如 如 如 如 如 如 如 如 如 如 如 如 如 如 如 如 如 如 如 如 如 如 如 如 如 如 , , , . The reinforcing plate according to claim 2, wherein the polyimine layer has a thickness of 25/zm to 75/zin. The reinforcing plate according to claim 2, wherein the polyether quinone layer has a thickness of 25em~75em». A reinforcing flexible circuit board comprising a flexible circuit board and being attached to a flexible circuit board. A reinforcing plate for a reinforcing plate according to any one of claims 4 to 4. The reinforcing flexible circuit board of claim 5, wherein the reinforcing plate is adhered to the flexible circuit board by an adhesive layer, and the adhesive layer is composed of a polyether quinone material, The structural formula A of the amine material is: 097100308 Form No. A0101 Page 13 of 17 1003448511-0 1359734 100 years. December, revised correction page 7. The reinforced flexible circuit board according to claim 6, wherein the adhesive layer has a thermal expansion coefficient of 16x1 〇_6~18x 1〇_6Κ-ι. 8. The reinforcing flexible circuit board of claim 6, wherein the adhesive layer has a thickness of 25; am~70/ζιη. 097100308 Form No. A0101 Page 14 of 17 1003448511-0