KR101085726B1 - Rigid flexible printed circuit board and method for manufacturing of the same - Google Patents

Abstract

The present invention provides a flexible printed circuit board. In the flexible printed circuit board according to the embodiment of the present invention, the rigid part having an outer ground line, and the bent part which is bent by the operation of the hard part and the non-bent part which is not bent even when the hard part is operated are operated. And a flexible portion having a first insulating layer, a first metal layer covering an entire surface of the first insulating layer and having an inner ground line, a coverlay covering the first metal layer, and a coverlay and a first layer. 1 includes a conductive layer covering at least one of the back surface of the insulating layer and having a junction portion electrically connected to the internal ground wiring.

Rigid Printed Circuit Board, RF PCB, Ground, Ground

Description

Rigid FLEXIBLE PRINTED CIRCUIT BOARD AND METHOD FOR MANUFACTURING OF THE SAME

The present invention relates to a printed circuit board, and more particularly, to a flexible printed circuit board and a method of manufacturing the same improved radiation characteristics.

Slide cables are used to electrically connect the main board and the sub board that are electrically separated from electronic devices such as notebook computers, mobile devices, and portable terminals. Slide cables usually include rigid flexible printed circuit boards (RF PCBs). The flexible printed circuit board includes a flexible portion having flexibility, a first rigid portion provided at one end of the flexible portion, and a second rigid portion provided at the other end of the flexible portion. The first hard part is connected to the main board and the second hard part is connected to the sub board. Accordingly, the flexible printed circuit board has a structure in which the flexible part is repeatedly bent and unfolded according to the operation of the main board and the sub board. Recently, due to the high integration and small weight of the electronic device, the bending radius of the flexible part of the flexible printed circuit board is gradually decreasing, and thus a slide cable having a high flexibility is required. However, as thinning, high integration, and small weight of the flexible printed circuit board progress, electric connection error of the flexible printed circuit board is caused by Electro Static Discharge (ESD) and ELMI (Electromagnetic Interferenc: EMI). Problems such as errors, malfunctions, and noise generation are increasing.

The problem to be solved by the present invention is to provide a flexible printed circuit board with improved radiation characteristics.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method of manufacturing a flexible printed circuit board having improved radiation characteristics.

The flexible printed circuit board according to the present invention has a flexible part having an outer ground line, a flexible part having a bend caused by the operation of the hard part, and a flexible part having a non-bend part which is not bent even when the hard part is operated. And a flexible portion, wherein the flexible portion includes a first insulating layer, a first metal layer covering an entire surface of the first insulating layer and having an inner ground line, a coverlay covering the first metal layer, and the coverlay and And a conductive layer covering at least one of the rear surfaces of the first insulating layer and having a junction portion electrically connected to the internal ground wiring.

According to an embodiment of the present invention, the junction portion may be provided in the non-bending portion.

According to an embodiment of the present invention, the coverlay includes a first recessed portion exposing the first metal layer, the conductive layer covers the entire surface of the coverlay, and through the first recessed portion to the internal ground wiring. It may have a first conductive layer to be bonded.

According to an embodiment of the present invention, the coverlay includes a first recessed portion exposing the first metal layer, and the first insulating layer includes a second recessed portion exposing the first metal layer, wherein the conductive layer is Covering the front surface of the coverlay, covering the first conductive layer having a first bonding portion bonded to the internal ground wiring through the first recessed portion and the back surface of the first insulating layer, and through the second recessed portion It may include a second conductive layer having a second bonding portion bonded to the internal ground wiring.

According to an embodiment of the present invention, the coverlay includes a first recessed portion exposing the first metal layer, and the hard portion is electrically connected to at least one of the second metal layer and the first metal layer and the second metal layer. And vias, wherein the conductive layer is bonded to at least one of the first and second vias connected to the inner ground wiring through the first recess and the at least one of the inner ground wiring and the outer ground wiring. It may include a second bonding portion to be bonded.

According to an embodiment of the present invention, the coverlay includes a first recessed portion exposing the first metal layer, the first insulating layer includes a second recessed portion exposing the first metal layer, and the hard portion is formed of a first recessed portion. A second metal layer, a first via electrically connected to at least one of the first metal layer and the second metal layer on a front surface of the hard part, and a second via electrically connected to the first metal layer on a rear surface of the hard part; The conductive layer may include a first conductive layer covering a front surface of the coverlay and a front surface of the hard portion, and a second conductive layer covering a rear surface of the first insulating layer and a rear surface of the hard portion. The layer includes a first junction portion bonded to the inner round wiring through the first depression and a third junction portion bonded to the first via, wherein the second conductive portion It may include a fourth joint portion that is joined to the second joining portion and the second via is joined to the internal ground wiring through the second depression.

According to the present invention, a method of manufacturing a flexible printed circuit board may include forming a flexible part and forming a flexible part having a bent portion in which bending occurs according to an operation of the rigid part and a non-bending portion in which the rigid portion does not bend even when the rigid portion is operated. The step of forming the flexible portion may include forming a first metal layer covering the first insulating layer and the first insulating layer and having an inner ground line, and covering the first metal layer. Forming a ray and forming at least one of a front surface of the coverlay and a rear surface of the first insulating layer, and forming a conductive layer electrically connected to the internal ground line.

According to an embodiment of the present invention, the forming of the conductive layer may include a metal target including at least one of silver (Ag), gold (Au), aluminum (Al), magnesium (Mg), and copper (Cu). This can be done by performing an ion sputtering process to be used.

According to an embodiment of the present invention, the conductive layer may be used as an internal ground line for discharging the residual current of the flexible portion.

According to an embodiment of the present invention, the forming of the coverlay may include preparing a coverlay forming film having a first depression, wherein the first depression is aligned to expose the first metal layer at the non-bending portion. Forming a coverlay forming film on a first metal layer, and forming the conductive layer includes forming a metal film covering the first metal layer exposed through the coverlay and the first recessed portion. Can be.

According to an embodiment of the present invention, the forming of the coverlay may include preparing a coverlay forming film having a first depression, wherein the first depression is aligned to expose the first metal layer at the non-flexion portion. 1. The method may include forming the coverlay forming layer on the metal layer, and preparing the first insulating layer may include forming a second recessed portion exposing the first metal layer in the non-bending portion, wherein the conductive layer is formed. Forming a first conductive layer covering a front surface of the coverlay and having a first bonding portion bonded to the inner ground wiring through the first recess, and covering a rear surface of the first insulating layer. And forming a second conductive layer having a second bonding portion bonded to the internal ground line through the second recessed portion.

According to an embodiment of the present invention, the forming of the coverlay may include preparing a coverlay forming film having a first depression, wherein the first depression is aligned to expose the first metal layer at the non-bending portion, And forming the coverlay forming layer on the first metal layer, wherein forming the hard part comprises sequentially forming a prepreg layer, a second metal layer, and a second insulating layer at both end regions of the flexible part. Forming a through hole penetrating a second insulating layer, the second metal layer, and the prepreg layer; and a via electrically connected to at least one of the first metal layer and the second metal layer in the through hole. ), Wherein the forming of the conductive layer comprises: forming a first conductive layer bonded to the first metal layer and the via exposed through the first depression; It may include the step of forming the conductive layer.

According to an embodiment of the present invention, the forming of the coverlay may include preparing a coverlay forming film having a first depression, wherein the first depression is aligned to expose the first metal layer at the non-bending portion, And forming the coverlay forming film on a first metal layer, and preparing the first insulating layer includes forming a second recessed portion exposing the first metal layer in the non-bending portion, wherein the rigid portion is formed. The step of forming the step of forming a prepreg layer, a second metal layer and a second insulating layer in the both end regions of the flexible portion, the second insulating layer, the second insulating layer on one side of the hard portion based on the flexible portion Forming a first through hole penetrating the metal layer and the prepreg layer, and forming at least one of the first metal layer and the second metal layer in the first through hole. Forming a first via that is miraculously connected, forming a second through hole penetrating the second insulating layer, the second metal layer, and the prepreg layer on the other side of the hard part; and And forming a second via electrically connected to the first metal layer in a second through hole, wherein forming the conductive layer comprises: the first metal layer exposed through the first recess and the first metal layer; The method may include forming a first conductive layer bonded to a first via and forming a second conductive layer bonded to the first metal layer and the second via exposed through the second recess.

The flexible printed circuit board according to the present invention includes a flexible part and a rigid part, and includes a conductive layer covering the flexible part and grounded to an internal ground wiring of the flexible part. Accordingly, the present invention can effectively ground the current of the flexible printed circuit board to the internal ground wiring, thereby providing a flexible printed circuit board having improved radiation characteristics.

The method for manufacturing a flexible printed circuit board according to the present invention may include a flexible part and a rigid part, and may manufacture a flexible printed circuit board having a conductive layer covering the flexible part and having a conductive layer grounded to an internal ground wiring of the flexible part. . Accordingly, the present invention can provide a method of manufacturing a flexible printed circuit board having improved radiation characteristics by effectively grounding the current of the printed circuit board to the internal ground wiring.

BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention and the manner of achieving them will become apparent with reference to the embodiments described in detail below with reference to the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. The embodiments may be provided to make the disclosure of the present invention complete, and to fully inform the scope of the invention to those skilled in the art. Like reference numerals refer to like elements throughout the specification.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. In the present specification, the singular form includes plural forms unless otherwise specified in the specification. It is to be understood that the terms 'comprise', and / or 'comprising' as used herein may be used to refer to the presence or absence of one or more other components, steps, operations, and / Or additions.

Hereinafter, a flexible printed circuit board and a manufacturing method thereof according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

1 is a perspective view illustrating a flexible printed circuit board according to an exemplary embodiment of the present invention, and FIG. 2 is a cross-sectional view taken along line II ′ of FIG. 1.

1 and 2, the flexible printed circuit board 100 according to an exemplary embodiment of the present invention may include a flexible part 110 having flexibility and a rigid part 120 having non-flexibility (ie, rigidity). ) May be included. The flexible portion 110 may generally have a bend shape. The hard part 120 may include a first hard part 121 connected to one end of the soft part 110 and a second hard part 122 connected to the other end of the soft part 110. The flexible part 110 may include a bend A1 and a non- bend A2. The bend A1 is a region where bending occurs according to the relative operation of the first and second hard parts 121 and 122, and the non-bending part A2 is the first and second hard parts 121 and 122. It may be an area in which bending does not occur even when a relative operation of) occurs. The curved portion A1 may be a central region of the flexible portion 110, and the non-curved portion A2 may be a region of the flexible portion 110 adjacent to the hard portion 120.

The flexible part 110 may include a flexible plate 112 and a coverlay 114. The flexible plate 112 may include a first insulating layer 112a and a first metal layer 112b covering the entire surface of the first insulating layer 112a. The first insulating layer 112a may be made of a polyimide material, and the first metal layer 112b may be made of copper (Cu). The coverlay 114 may conformally cover the entire surface of the first metal layer 112b. The coverlay 114 may have at least one first recessed portion 114a exposing the first metal layer 112b. The first recessed portion 114a may be provided at the non-bending portion A2 of the flexible portion 110.

The hard part 120 may be provided at both end regions B of the soft part 110. For example, the first hard part 121 may be provided at one end area of the flexible part 110, and the second hard part 122 may be provided at the other end area of the flexible part 110. The first hard part 121 and the second hard part 122 may have substantially the same internal structure. As an example, the first and second hard parts 121 and 122 may be formed of a prepreg layer 124, a second metal layer 126, and a stack sequentially formed on both sides of an edge area of the soft part 110, respectively. It may have a second insulating layer 126. The prepreg layer 124 may be provided so that the edge region of the flexible portion 110 is inflexible. Both end regions B of the flexible part 110 may be inflexible by the prepreg layer 124. The second metal layer 125 may include an outer circuit line. In addition, the second metal layer 125 may further include an outer ground line. The insulating layer 126 may cover the second metal layer 125 to protect it from the external environment. The insulating layer 126 may be made of a solder resist material.

The flexible printed circuit board 100 may further include at least one conductive layer. As an example, the flexible printed circuit board 100 may include a first conductive layer 130. The first conductive layer 130 may be formed to cover up to a partial region of the front surface of the flexible part 120 and the front surface of the flexible part 110. The first conductive layer 130 may be formed of a metal material including silver (Ag). Alternatively, the first conductive layer 130 may include at least one of gold (Au), aluminum (Al), magnesium (Mg), copper (Cu), nickel (Ni), titanium (Ti), and tungsten (W). It may be formed of a metal material containing. Meanwhile, the first conductive layer 130 may be electrically connected to the internal ground line of the first metal layer 112b through the first recessed portion 114a. To this end, the first conductive layer 130 may have a junction portion 132 bonded to the first metal layer 112b through the first recessed portion 114a. Since the residual current of the flexible printed circuit board 100 is discharged (ie, grounding) through the bonding portion 132, the flexible printed circuit board 100 may have improved electrical radiation characteristics. have. In addition, the bonding portion 132 of the first conductive layer 130 may be bonded to the first metal layer 112b at the position of the non-bending portion A2. The non-bending portion A2 is a region where bending does not occur even when the first and second rigid portions 121 and 122 operate, and thus, the joint portion 132 is generated by the operation of the rigid portion 120. Physical damage can be prevented.

Subsequently, the manufacturing process of the flexible printed circuit board according to the embodiment of the present invention will be described in detail. Here, the contents satisfied with respect to the flexible printed circuit board according to the embodiment of the present invention described above may be omitted or simplified.

3 is a flowchart illustrating a method of manufacturing a flexible printed circuit board according to an exemplary embodiment of the present invention. 4A to 4C are diagrams for describing a manufacturing process of a flexible printed circuit board according to an exemplary embodiment of the present invention.

Referring to FIGS. 3 and 4A, the flexible plate 112 may be prepared (S110). For example, the first metal layer 112b may be formed on the entire surface of the first insulating layer 112a having flexibility. The first insulating layer 112a may be formed of a polyimide material, and the first metal layer 112b may be formed of a metal including copper (Cu). However, materials of the first insulating layer 112a and the first metal layer 112b may not be limited thereto. A predetermined patterning process may be performed on the first metal layer 112b to form a metal pattern on the first insulating layer 112a. Accordingly, the first metal layer 112b having an inner circuit line on the first insulating layer 112a and an inner ground line for grounding the flexible printed circuit board. This can be formed.

A coverlay 114 may be formed to cover the first metal layer 112b and have a first recessed portion 114 exposing the first metal layer 112b (S120). As an example, the forming of the coverlay 114 may be performed by covering the coverlay forming film on which the first recessed portion 114a is formed on the entire surface of the first metal layer 112b. In this case, the coverlay forming film may be formed on the first metal layer 112b such that the first recessed portion 114a is aligned with the non-bending portion A2 of the flexible plate 112. As another example, the forming of the coverlay 114 may include forming a coverlay forming film that conformally covers the entire surface of the first metal layer 112b, and then etching the coverlay forming film. The first recessed part 114a may be formed through the process. As the etching process, a dry etching process using a photoresist may be used.

3 and 4B, the prepreg layer 122, the second metal layer 125, and the second insulating layer 126 may be sequentially formed (S130). The forming of the prepreg layer 122 may be performed by forming a rigid layer having rigidity at both end regions B of the flexible part 110. The forming of the second metal layer 125 may include forming an outer circuit line on the prepreg layer 122. In addition, the forming of the second metal layer 125 may include forming an outer ground line on the prepreg layer 122. The forming of the second insulating layer 126 may include forming a layer of a solder resist material covering the external circuit wiring.

3 and 4C, the first conductive layer 130 covering the first metal layer 112b exposed through the coverlay 114 and the first recessed portion 114a may be formed (S140). For example, the forming of the first conductive layer 130 may include performing an ion sputtering process using a metal target on the entire surface of the coverlay 114 and the first metal layer 112b. It may include. As an example, an ion sputtering apparatus (not shown) having a process chamber having a metal target disposed therein may be prepared. The metal target may include a metal material for forming the first conductive layer 130. For example, the metal target may be made of a metal material including silver (Ag). Alternatively, the metal target may be a metal material including at least one of gold (Au), aluminum (Al), magnesium (Mg), copper (Cu), nickel (Ni), titanium (Ti), and tungsten (W). Can be done. The ion sputtering apparatus may further include a plasma generator. The plasma generator may form a plasma atmosphere in the chamber during the ion sputtering process. By performing the plasma ion sputtering process using the ion sputtering apparatus as described above, the front surface of the coverlay 114, the partial region of the second insulating layer 126, and the first exposed portion exposed through the first recess 114a. A conductive film may be formed to conformally cover the first metal layer 114. Accordingly, the first conductive layer 130 having the junction portion 132 electrically connected to the internal ground line of the first metal layer 114 through the first recessed portion 114a may be formed. As the first conductive layer 130 is grounded to the first metal layer 114 by the bonding portion 132, the flexible printed circuit board may be effectively grounded by the first metal layer 114. The radiation characteristics of the flexible printed circuit board can be improved.

On the other hand, when the first conductive layer 130 is formed through the ion sputtering process as described above, the first conductive layer 130 in the stepped portion 133 between the flexible portion 110 and the hard portion 120. Can be effectively formed. For example, when the first conductive layer is formed by an application process using a metal paste, a taping process using a conductive tape, and a screen printing process instead of an ion sputtering process, a nonuniform metal film may be formed on the stepped portion 133. Can be. In this case, an electrical conduction state between the first conductive layer 130 and the external circuit wiring of the second metal layer 126 may be poor. In particular, when the step height of the stepped portion 133 is approximately 150 μm or more, when the metal film is formed by the above-described coating process, taping process and screen printing process using the metal paste, the stepped portion 133 may be formed on the metal film. Cracks may occur. In this case, an electrical short may occur between the first conductive layer 130 and the external circuit wiring. To prevent this, a process of applying silver (Ag) paste to the stepped portion 133 and a process of finishing with a conductive tape may be added. However, in the case of using the above-described ion sputtering method, since the first conductive layer 130 can be effectively formed in the stepped portion 133, additional processes such as the silver paste coating process and the conductive tape finishing process described above are not provided. It does not need to be performed.

Hereinafter, a flexible printed circuit board according to modified examples of the present invention will be described in detail. Here, the overlapping contents for the flexible printed circuit board according to the embodiment of the present invention described above may be omitted or simplified. In addition, the manufacturing process of the flexible printed circuit boards according to the modified examples to be described later can be derived by those skilled in the art through the manufacturing process of the flexible printed circuit board 100 described above, a detailed description thereof will be omitted.

5 is a view showing a flexible printed circuit board according to a modification of the present invention. Referring to FIG. 5, the flexible printed circuit board 100a according to the modified embodiment of the present invention may include the flexible part 110a, the rigid part 120, the first conductive layer 130, and the second conductive layer 140. It may include. Since the structures of the hard part 120 and the first conductive layer 130 have substantially the same structures as the hard part 120 and the first conductive layer 130 described above with reference to FIG. 2, detailed descriptions thereof will be omitted. do.

The flexible portion 110a may include a flexible plate 113 and a coverlay 114. The flexible plate 113 may include a first insulating layer 113 having at least one second recessed portion 113a and a first metal layer 112b covering an entire surface of the first insulating layer 113. . The second recess 113a may expose a rear surface of the first metal layer 112b. Here, the first conductive layer 130 is formed to cover the coverlay 114 on the front surface of the flexible plate 113, the second conductive layer 140 is formed on the back surface of the flexible plate 113 Can be covered Accordingly, the second conductive layer 140 may have a second bonding portion 142 bonded to the first metal layer 112b through the second recess 113a. The second conductive layer 140 may be formed through the ion sputtering process described above in the embodiment of the present invention. In this case, the second conductive layer 140 may be simultaneously formed in-situ together with the first conductive layer 130. Accordingly, the first conductive layer 130 may be formed without cracks at uniform thicknesses on the stepped portions 133 and 135 between the flexible part 110 and the hard part 120.

The flexible printed circuit board 100a may have a structure in which the first conductive layer 130 and the first conductive layer 140 are grounded to an internal ground line of the first metal layer 112b. More specifically, the first conductive layer 130 may be grounded to the internal ground wiring through the first recessed portion 114a of the coverlay 114 on the front surface of the flexible plate 113. The second conductive layer 140 may be grounded to the internal ground line through the second recess 113a of the first insulating layer 113 on the rear surface of the flexible plate 113. Accordingly, the flexible printed circuit board 100a effectively grounds an overcurrent to the internal ground line, thereby improving radiation characteristics.

6 is a view showing a flexible printed circuit board according to another modification of the present invention. Referring to FIG. 6, the flexible printed circuit board 100b according to another modified embodiment of the present invention may include the flexible part 111 and the rigid part 120a. Since the flexible part 111 has a structure substantially similar to the flexible part 110 described above with reference to FIG. 2, a detailed description thereof will be omitted. The hard part 120a may include a first hard part 121a and a second hard part 122. The first hard part 121a may include a prepreg layer 124, a second metal layer 125, and a second insulating layer 126 that are sequentially stacked on both end regions C of the flexible part 110. It may include. In addition, the first hard part 121a may have at least one via (127). The via 127 may be provided to penetrate the prepreg layer 124, the second metal layer 125, and the second insulating layer 126. To this end, the first hard part 121a may have the second insulating layer 126, the second metal layer 125, and the prepreg layer 124 at both end regions B of the flexible part 111. It may have a via hole penetrating through (129). The via 127 may be formed to be electrically connected to at least one of the first metal layer 112b and the second metal layer 125 in the via hole 129. Meanwhile, the second hard part 122 may have a structure substantially the same as that of the second hard part 122 described with reference to FIG. 2.

The first conductive layer 131 of the flexible part 110 may be formed to cover the entire surface of the coverlay 114 and a portion of the hard part 120a on the flexible plate 112. The first conductive layer 131 may be bonded to the first metal layer 112b exposed through the first recess 114a in the non-bending portion A2. In addition, the first conductive layer 131 may include at least one of the first metal layer 112b and the second metal layer 125 through the via 127 in the region C in which the hard part 120a is formed. Can be connected to. Accordingly, the first conductive layer 131 may include a first bonding portion 132 bonded to the first metal layer 112b and a third bonding portion 134 bonded to the via 127. . Meanwhile, the first conductive layer 131 may be formed through the ion sputtering process described above, and thus the first conductive layer 131 may be formed without cracks at a uniform thickness on the stepped portion 133. .

In the above-described flexible printed circuit board 100b, a first conductive layer 131 is grounded to the internal ground wiring of the first metal layer 112b by the first bonding portion 132, and the third bonding portion 134 is provided. ) May have a structure that is respectively grounded to the external ground line of the second metal layer 125. In addition, the flexible printed circuit board 100b may have a structure in which the first conductive layer 131 is connected to an internal ground line of the first metal layer 112b by the third bonding portion 134. have. Accordingly, the flexible printed circuit board 100b is effectively grounded to the external and internal ground wires, so that the radiation characteristics can be improved.

7 is a view showing a flexible printed circuit board according to another modified embodiment of the present invention. Referring to FIG. 7, the flexible printed circuit board 100c according to another modified embodiment of the present invention may include a flexible portion 111a and a rigid portion 120b. The flexible portion 111a has a structure substantially similar to the flexible portion 110a described above with reference to FIG. 5, and a detailed description thereof will be omitted. The hard part 120b may include a first hard part 121b and a second hard part 122. The first hard part 121b may include a prepreg layer 124, a second metal layer 125, and a second insulating layer 126 that are sequentially stacked on both end regions C of the flexible part 110. It may include. In addition, the first rigid portion 121b may include a first via 127 and a second via 128. The first via 127 is provided to the first rigid part 121b formed at one side (that is, the front side) of the flexible part 111a based on the flexible part 111a, and the second via 128 is provided. ) May be provided to the first rigid part 121b formed at the other side (ie, the back side) of the flexible part 111b. The first and second vias 127 and 128 may be provided to penetrate the prepreg layer 124, the second metal layer 126, and the second insulating layer 126. To this end, the first hard part 121a penetrates through the second insulating layer 126, the second metal layer 125, and the prepreg layer 124 in the region C where the hard part 120b is formed. The third and fourth via holes 129a and 129b may be formed. The first via 127 may be electrically connected to at least one of the first metal layer 113 and the second metal layer 125 in the third via hole 129a. In contrast, the second via 128 may be electrically connected to the first metal layer 113 in the fourth via hole 129b. Meanwhile, the second hard part 122 may have a structure substantially the same as that of the second hard part 122 described with reference to FIG. 2.

The flexible part 110 may include a first conductive layer 131 and a second conductive layer 141. The first conductive layer 131 may be formed to cover the entire surface of the coverlay 114 and a portion of the entire surface of the hard part 120b. The second conductive layer 141 may be formed to cover the rear surface of the first insulating layer 112a of the flexible plate 112 and a partial region of the rear surface of the hard part 120b. The first conductive layer 131 is bonded to the first metal layer 113 exposed through the first recess 114a at the non-bending portion A2 and in the region C in which the hard portion 120b is formed. May be bonded to the first via 127. In addition, the second conductive layer 141 is bonded to the first metal layer 113 exposed through the second recess 113a at the non-bending portion A2, and the second vias are formed at the region C. 128). Accordingly, the first conductive layer 131 includes a first bonding portion 132 bonded to the first metal layer 113 and a third bonding portion 134 bonded to the first via 127. The second conductive layer 141 may include a second bonding portion 142 bonded to the first metal layer 113 and a fourth bonding portion 144 bonded to the second via 128. . Meanwhile, the first and second conductive layers 131 and 141 may be formed through the ion sputtering process described above, and thus the first and second conductive layers 131 and 141 may be formed in the flexible portion ( The stepped portions 133 and 135 between the 111a) and the hard part 120b may be formed without cracks at a uniform thickness.

In the above flexible printed circuit board 100c, the first conductive layer 131 is grounded to the internal ground wiring of the first metal layer 113 by the first bonding portion 132, and the third bonding portion ( 134 may have a structure that is respectively grounded to at least one of the internal ground line and the external ground line of the second metal layer 125. In addition, the second conductive layer 141 is grounded to the internal ground wiring by the second bonding portion 142, and the inner ground wiring and the second metal layer 126 by the fourth bonding portion 144. It may have a structure that is grounded to at least one of the external ground wiring. Accordingly, since the flexible printed circuit board 100c is effectively grounded to the external and internal ground wires, radiation characteristics may be improved.

The foregoing detailed description illustrates the present invention. It is also to be understood that the foregoing is illustrative and explanatory of preferred embodiments of the invention only, and that the invention may be used in various other combinations, modifications and environments. That is, changes or modifications may be made within the scope of the concept of the invention disclosed in this specification, the scope equivalent to the disclosed contents, and / or the skill or knowledge in the art. The foregoing embodiments are intended to illustrate the best mode contemplated for carrying out the invention and are not intended to limit the scope of the present invention to other modes of operation known in the art for utilizing other inventions such as the present invention, Various changes are possible. Accordingly, the detailed description of the invention is not intended to limit the invention to the disclosed embodiments. In addition, the appended claims should be construed as including steps in other embodiments.

1 is a perspective view illustrating a flexible printed circuit board according to an exemplary embodiment of the present invention.

FIG. 2 is a cross-sectional view taken along the line II ′ of FIG. 1.

3 is a flowchart illustrating a method of manufacturing a flexible printed circuit board according to an exemplary embodiment of the present invention.

4A to 4C are diagrams for describing a manufacturing process of a flexible printed circuit board according to an exemplary embodiment of the present invention.

5 is a view showing a flexible printed circuit board according to a modification of the present invention.

6 is a view showing a flexible printed circuit board according to another modification of the present invention.

7 is a view showing a flexible printed circuit board according to another modified embodiment of the present invention.

Description of the Related Art [0002]

100: flexible printed circuit board

110: flexible part

112: flexible plate

114: coverlay

114a: first depression

120: hard part

130: first conductive layer

132: first ground portion

140: second conductive layer

142: second ground portion

Claims (13)

A hard part having an outer ground line; And It includes a flexible portion having a bending portion is generated by the operation of the rigid portion and a non-bending portion that does not occur bending even when the hard portion is operated, The flexible portion: A first insulating layer; A first metal layer covering an entire surface of the first insulating layer and having an inner ground line; A coverlay covering the first metal layer; And And a conductive layer covering at least one of the coverlay and the back surface of the first insulating layer and having a bonding portion electrically connected to the internal ground wiring. The method of claim 1, The bonded portion is a flexible printed circuit board provided in the non-flexed portion. The method according to claim 1 or 2, The coverlay includes a first depression that exposes the first metal layer, And the conductive layer covers the entire surface of the coverlay and has a first conductive layer bonded to the internal ground wiring through the first recessed portion. The method according to claim 1 or 2, The coverlay includes a first depression that exposes the first metal layer, The first insulating layer includes a second recessed portion exposing the first metal layer, The conductive layer is: A first conductive layer covering a front surface of the coverlay and having a first bonding portion bonded to the internal ground wiring through the first depression; And And a second conductive layer covering a rear surface of the first insulating layer and having a second bonding portion bonded to the internal ground wiring through the second recessed portion. The method according to claim 1 or 2, The coverlay includes a first depression that exposes the first metal layer, The hard part is: A second metal layer; And A via electrically connected to at least one of the first metal layer and the second metal layer; The conductive layer is: A first junction portion joined to the internal ground line through the first recess; And And a second bonding portion bonded to the via and bonded to at least one of the inner ground wiring and the outer ground wiring. The method according to claim 1 or 2, The coverlay includes a first depression that exposes the first metal layer, The first insulating layer includes a second recessed portion exposing the first metal layer, The hard part is: A second metal layer; A first via electrically connected to at least one of the first metal layer and the second metal layer on a front surface of the hard part; And A second via electrically connected to the first metal layer on a rear surface of the hard part, The conductive layer is: A first conductive layer covering an entire surface of the coverlay and an entire surface of the hard part; And A second conductive layer covering a rear surface of the first insulating layer and a rear surface of the hard part; The first conductive layer is: A first junction portion joined to the internal ground line through the first recess; And A third junction portion bonded to the first via, The second conductive layer is: A second junction portion joined to the internal ground line through the second depression portion; And A flexible printed circuit board comprising a fourth bonding portion bonded to the second via. Forming a hard portion; And Forming a flexible portion having a bending portion that is bent in accordance with the operation of the rigid portion and a non-bending portion that does not occur bending even when the hard portion is operated, Forming the flexible portion is: Forming a first metal layer covering a first insulating layer and the first insulating layer and having an inner ground line; Forming a coverlay covering the first metal layer; And Forming a conductive layer covering at least one of a front surface of the coverlay and a rear surface of the first insulating layer and electrically connected to the internal ground wirings. The method of claim 7, wherein The conductive layer may be formed by performing an ion sputtering process using a metal target including at least one of silver (Ag), gold (Au), aluminum (Al), magnesium (Mg), and copper (Cu). Method for manufacturing a flexible printed circuit board. The method of claim 7, wherein The conductive layer is a flexible printed circuit board manufacturing method used as an internal ground wiring for discharging the residual current of the flexible portion. The method according to any one of claims 7 to 9, Forming the coverlay is: Preparing a coverlay forming film having a first depression; Forming the coverlay forming film on the first metal layer while the first recess is aligned to expose the first metal layer at the non-bending portion, The forming of the conductive layer may include forming a metal film covering the first metal layer exposed through the coverlay and the first recessed portion. The method according to any one of claims 7 to 9, Forming the coverlay is: Preparing a coverlay forming film having a first depression; Forming the coverlay forming layer on the first metal layer while the first recess is aligned to expose the first metal layer at the non-bending portion, Preparing the first insulating layer may include forming a second recessed portion exposing the first metal layer in the non-flexed portion, Forming the conductive layer is: Forming a first conductive layer covering a front surface of the coverlay, the first conductive layer having a first bonding portion bonded to the internal ground wiring through the first depression; And Forming a second conductive layer covering a rear surface of the first insulating layer, the second conductive layer having a second bonding portion bonded to the inner ground wiring through the second recessed portion. The method according to any one of claims 7 to 9, Forming the coverlay is: Preparing a coverlay forming film having a first depression; Forming the coverlay forming film on the first metal layer while the first recess is aligned to expose the first metal layer at the non-bending portion, Forming the hard portion is: Sequentially forming a prepreg layer, a second metal layer, and a second insulating layer at both end regions of the flexible portion; Forming a through hole penetrating the second insulating layer, the second metal layer, and the prepreg layer; And Forming a via in the through hole, the via electrically connected to at least one of the first metal layer and the second metal layer; Forming the conductive layer is: Forming a first conductive layer bonded to the first metal layer and the via exposed through the first recessed portion. The method according to any one of claims 7 to 9, Forming the coverlay is: Preparing a coverlay forming film having a first depression; Forming the coverlay forming film on the first metal layer while the first recess is aligned to expose the first metal layer at the non-bending portion, Preparing the first insulating layer may include forming a second recessed portion exposing the first metal layer in the non-flexed portion, Forming the hard portion is: Sequentially forming a prepreg layer, a second metal layer, and a second insulating layer in both end regions of the flexible portion; Forming a first through hole penetrating the second insulating layer, the second metal layer, and the prepreg layer on one side of the hard part based on the flexible part; Forming a first via electrically connected to at least one of the first metal layer and the second metal layer in the first through hole; Forming a second through hole penetrating the second insulating layer, the second metal layer, and the prepreg layer on the other side of the hard part; Forming a second via in the second through hole, the second via being electrically connected to the first metal layer; Forming the conductive layer is: Forming a first conductive layer bonded to the first metal layer and the first via exposed through the first depression; And And forming a second conductive layer bonded to the first metal layer and the second via exposed through the second recessed portion.

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