Rigid-flexible printed circuit board and method of manufacturing the same

Description

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

FIGS. 1A to 1N are process diagrams showing a conventional method of manufacturing a rigid-flexible printed circuit board;

FIG. 2 is a sectional view showing a rigid-flexible printed circuit board according to an embodiment of the present invention;

FIG. 3 is a flow chart schematically showing a method of manufacturing a rigid-flexible printed circuit board according to a first embodiment of the present invention;

FIG. 4A to 4K are process diagrams sequentially showing the method of manufacturing the rigid-flexible printed circuit board in FIG. 3;

FIG. 5 is a flow chart schematically showing a method of manufacturing a rigid-flexible printed circuit board according to a second embodiment of the present invention;

FIG. 6A to 6I are process diagrams sequentially showing the method of manufacturing the rigid-flexible printed circuit board in FIG. 5;

FIG. 7 is a flow chart schematically showing a method of manufacturing a rigid-flexible printed circuit board according to a third embodiment of the present invention; and

FIG. 8A to 8I are process diagrams sequentially showing the method of manufacturing the rigid-flexible printed circuit board in FIG. 7.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Preferred embodiments will be described with reference to the accompanying drawings below.

FIG. 2 is a sectional view showing a rigid-flexible printed circuit board according to an embodiment of the present invention.

The rigid-flexible printed circuit board 200 includes a rigid region and a flexible region.

The rigid region is formed in a predetermined region of a double-sided FCCL. The rigid region includes a double-sided FCCL 110 in which inner circuit patterns 114 are formed on both sides thereof, coverlays 120 and insulation layers 132 and 134 layered on two sides of the double sided FCCL 110, a plated blind via hole 146 formed in the insulation layer 132 and the upper coverlay 120 and a PTH 142 configured to electrically connect the upper and lower portions of a plating layer 160, copper foil layers 136 and 138 interposed between the insulation layers 132 and 134 and the plating layer 160, outer circuit patterns 170 formed on the insulation layers 132 and 134 using the plating layer 160 and the copper foil layers 136 and 138, and solder resists 180 formed to expose portions of the outer circuit patterns 170.

The flexible region is formed in the region of the double-sided FCCL 110 other than the rigid region of the double-sided FCCL 110. The flexible region includes the double-sided FCCL 110 in which the inner circuit patterns 114 are formed on both sides of the double-sided FCCL 110, the coverlays 120 respectively layered on two sides of the double-sided FCCL 110 and respectively provided with first windows 118 having predetermined diameters, plating layers 174 respectively formed in the first windows 118, and conductive paste 190 applied on the outer sides of the flexible region to form ground shield layers.

Further, the flexible region further includes additional plating layer portions 172, having diameters respectively larger than the diameters of the first windows, on the portions of the coverlays 120 adjacent to the first windows 118. Each of the additional plating layers 172 extends from the plating layer 174 formed in each of the first windows 118, and is a portion of the plating layer 160 formed on the entire surface of the laminated body 140 to form the outer circuit patterns 170.

Further, a multi-layered flexible substrate may be formed by layering two or more double-sided FCCLs in the flexible region, and the first windows 118 are formed in the outermost copper foil layers of the double-sided FCCLs.

Further, a blind via hole (see 248 and 348 in FIG. 6 to 8) or an inner via hole (see 250 and 350 in FIG. 6 to 8) having a diameter smaller than the predetermined diameter may be formed in the flexible region to correspond to the plated first window 118 having a predetermined diameter. The additional plating portion (see 272 and 372 in FIG. 6 to 8) may also be formed on the coverlays adjacent to this via hole, and this via hole is referred to as a CL via hole.

Since this additional plating portion is provided, it is possible to increase the adhesive force between the coverlay and the plating layer.

FIG. 3 is a flow chart schematically showing a method of manufacturing a rigid-flexible printed circuit board according to a first embodiment of the present invention.

The method of manufacturing a rigid-flexible printed circuit board according to the first embodiment of the present invention is performed through the following steps.

First, a base substrate, in which coverlays are formed over two sides of a double-sided FCCL on both sides of which inner circuit patterns are formed, is provided (S110). Insulation layers and copper foil layers are layered on the portions of coverlays which are to be a rigid region of the double-sided FCCL (S120). A via hole is formed in the rigid region using a CO₂laser, and simultaneously first windows are formed in the coverlays of the flexible region (S130).

An entire plating layer is formed over the entire area, and outer circuit patterns including a region around the first window are formed from the plating layer (S140). Then, solder resists are applied in the rigid region to expose a portion of the outer circuit patterns (S150).

Accordingly, it is possible to manufacture a rigid-flexible printed circuit board having additional plating portions in accordance with features of the present invention.

FIG. 4A to 4K are process diagrams sequentially showing the method of manufacturing the rigid-flexible printed circuit board in FIG. 3.

As shown in FIG. 4A, a double-sided FCCL 110, in which copper foil layers 114 are respectively formed on two sides of a polyimide film 112, is provided, and, as shown in FIG. 4B, predetermined inner circuit patterns 116 are respectively formed on both sides of the polyimide film 112 using the copper foil layers 14.

As shown in FIG. 4C, a base substrate 130 is formed by layering coverlays 120 respectively throughout two sides of the double-sided FCCL 110 on which the inner circuit patterns are formed.

Here, before the coverlays are respectively layered on the double-sided FCCL, windows are not formed in the regions of the coverlays corresponding to the flexible region by previous processing, and the coverlays are directly layered on the entire surfaces of the double-sided FCCL, therefore it is not necessary to perform a process of provisionally layering the coverlays on the double-sided FCCL to conform to the circuit patterns formed on the double-sided FCCL.

As shown in FIG. 4D, after the base substrate 130 is formed, insulation layers 132 and 134 are respectively layered on the portions of the coverlays 120 which are to be a rigid region in the base substrate 130, and copper foil layers 136 and 138 having a size corresponding to that of the base substrate 130 are respectively layered over the insulation layers 132 and 134, thereby forming a laminated body 140.

Here, a prepreg, which is a mixed material of reinforcing base material and resin and is cured after it is heated and pressurized in a semi-cured state, may be used as each of the insulation layers 132 and 134.

As shown in FIG. 4E, a PTH 142 for electrically connecting the upper and lower portions of the laminated body 140 is formed in the rigid region of the laminated body 140 through a drilling process, and, as shown in FIG. 4F, a second window 144 is formed in a portion of the copper foil layer 136 of the rigid region, and portions of the copper foil layers 136 and 138 of the flexible region are simultaneously removed.

As shown in FIG. 4G, a blind via hole 146 is formed in the portion of the rigid region corresponding to the second window 144 using a CO₂laser, and first windows 118 are simultaneously formed in portions of the coverlays 120 in the flexible region using the CO₂laser.

As shown in FIG. 4H, a plating layer is formed by plating the entire surface of the laminated body 140 using copper, and, as shown in FIG. 4I, outer circuit patterns 170 are formed in the rigid region using the plating layer 160, and plating layers 174 in the first windows 118 and additional plating portions 172 adjacent thereto are formed in the flexible region. That is, the plating layers 174 in the first windows 118 and the additional plating portions 172 adjacent thereto are formed in the flexible region by removing the remainder of the plating layer, other than the portions of the plating layer in the first windows 118 and adjacent to the first windows 118, from the coverlays 120 using a method of partially removing the plating layer 160.

Further, each of the additional plating portions 172 has a diameter smaller than that of the first windows 118. As described in FIG. 2, the additional plating portions 172 extend respectively from the plating layers 174 formed in the first windows 118, and are portions of the entire plating layer 160 applied on the entire surface of the laminated body 140 to form the outer circuit patterns 170.

As shown in FIG. 4J, solder resists 180 are formed in the rigid region to expose portions of the outer circuit patterns 170, and, as shown in FIG. 4K, the rigid-flexible printed circuit board 200 is completed by applying conductive paste 190 to form ground shield layers on the surface of the laminated body 140 in the flexible region.

Here, if necessary, the ground shield layers may be applied or not applied.

As described above, the coverlays are respectively layered on both sides of the double-sided FCCL without previous processing thereof, the first windows are formed in the flexible region at the same time that the via hole is formed in the rigid region of the double-sided FCCL, and then the plating is performed on the laminated body, thereby decreasing the cost of processing the coverlays, and easily performing the process of provisionally layering the coverlays on the double-sided FCCL, compared to the conventional process of previously processing the coverlays and then provisionally layering them.

Further, the plating layers and the additional plating portions are formed in the flexible region, thereby decreasing the cost of applying and removing the resists, and preventing defects from occurring because the residual resist does not remain after removal of the resists, compared to the conventional process using the resists.

FIG. 5 is a flow chart schematically showing a method of manufacturing a rigid-flexible printed circuit board according to a second embodiment of the present invention.

The method of manufacturing a rigid-flexible printed circuit board according to the second embodiment of the present invention is performed through the following steps.

First, a base substrate, in which coverlays are respectively formed on two sides of a double-sided FCCL on both sides of which inner circuit patterns and first windows are respectively formed, is provided (S210). Insulation layers and copper foil layers are layered on the portions of coverlays which are to be the rigid region of the double-sided FCCL (S220). A via hole is formed in the rigid region using a CO₂laser and, simultaneously, another via hole is formed to correspond to the first window in the flexible region (S230).

An entire plating layer is formed over the entire area, and outer circuit patterns including a region around the first window are formed from the plating layer (S240). Then, solder resists are applied in the rigid region to expose a portion of the outer circuit patterns (S250).

FIG. 6A to 6I are process diagrams sequentially showing the method of manufacturing the rigid-flexible printed circuit board in FIG. 5.

The rigid-flexible printed circuit board 300 according to the second embodiment of the present invention, compared to that of the first embodiment of the present invention, is characterized in that a PTH is not formed in the rigid region, and a blind via hole and an inner via hole are formed in the flexible region.

As shown in FIG. 6A, a double-sided FCCL 210, in which copper foil layers 214 are respectively formed on two sides of a polyimide film 212, is provided, and, as shown in FIG. 6B, predetermined inner circuit patterns 216, a first window 218 and third windows 218a are formed using the copper foil layers 214.

Here, the region of the double-sided FCCL 210, in which the first window 218 and the third windows 218a are formed, is a flexible region, and the region of the double-sided FCCL 210 other than the flexible region is a rigid region.

Further, a blind via hole is formed in the first window 218 later, and an inner via hole is formed in the third windows 218a later.

As shown in FIG. 6C, a base substrate 230 is formed by layering coverlays 220 respectively throughout two sides of the double-sided FCCL 210 on which the inner circuit patterns, the first window 218 and the third windows 218a are formed.

As shown in FIG. 6D, after the base substrate 230 is formed, insulation layers 232 and 234 are respectively layered on the portions of coverlays 220 which are to be a rigid region in the base substrate 230, and copper foil layers 236 and 238, having a size corresponding to that of the base substrate 230, are respectively layered on the insulation layers 232 and 234, thereby forming a laminated body 240.

Here, a prepreg, which is a mixed material of reinforcing base material and resin, may be used as each of the insulation layers 232 and 234.

As shown in FIG. 6E, in the laminated body 240, a second window 244 is formed in a portion of the copper foil layer 236 in the rigid region, and portions of the copper foil layers 236 and 238 in the flexible region are simultaneously removed.

As shown in FIG. 6F, a blind via hole 246 is formed in the portion of rigid region corresponding to the second window 244 using a CO₂laser, and a blind via hole 248 and an inner via hole 250 are simultaneously formed in portions of the coverlays 220 corresponding to the first window 218 and the third window 218a, respectively, using the CO₂laser.

As shown in FIG. 6G, an entire plating layer 260 is formed by plating the entire surface of the laminated body 240 using copper, and, as shown in FIG. 6H, outer circuit patterns 270 are formed in the rigid region using the plating layer 260, and outer circuit patterns 270 including an additional plating portion 272 are formed in the flexible region.

Here, the plating layers 274 and the additional plating portions 272 are formed by removing the remainder of the plating layer on the coverlays 220 other than the plating layer on the coverlays 220 adjacent to the via holes 248 and 250 using the plating layer 260 plated in the flexible region.

Here, the diameters of the additional plating portions 272 are larger than the distances between the coverlays 220, and the distances between the coverlays 220 are larger than the diameters of the first windows 218. That is, it can be seen in the drawings that steps are formed from the additional plating portions into the via hole.

As described in the embodiment disclosed in FIG. 2 to 4, the additional plating portions 274 are extended from the plating layer formed in the via holes 248 and 250 in the flexible region, and are portions of the entire plating layer 160.

As shown in FIG. 6I, solder resists 280 are formed in the rigid region to expose portions of the outer circuit patterns 270, and thus the rigid-flexible printed circuit board 300 is completed.

Here, if necessary, the ground shield layers may applied or not applied.

FIG. 7 is a flow chart schematically showing a method of manufacturing a rigid-flexible printed circuit board according to a third embodiment of the present invention.

The method of manufacturing a rigid-flexible printed circuit board according to the third embodiment of the present invention is performed through the following steps.

First, a base substrate, in which coverlays are respectively formed on two sides of a double sided FCCL, on both sides of which inner circuit patterns and first window are formed, is provided (S310). Insulation layers and copper foil layers are respectively layered on the portions of coverlays which are to be a rigid region of the base substrate (S320). A via hole is formed in the rigid region using an ultraviolet laser, and simultaneously another via hole is formed in the flexible region (S330).

An entire plating layer is formed over the entire area, and outer circuit patterns including a region around the via holes are formed from the plating layer (S340). Then, solder resists are applied in the rigid region to expose a portion of the outer circuit patterns (S350).

FIG. 8A to 8I are process diagrams sequentially showing the method of manufacturing the rigid-flexible printed circuit board in FIG. 7.

The rigid-flexible printed circuit board 400 according to the second embodiment of the present invention, compared to that of the first embodiment of the present invention, is characterized in that a PTH is not formed in the rigid region, and a blind via hole and a inner via hole are formed in the flexible region, and, compared to that of the second embodiment of the present invention, is characterized in that the blind via hole and inner via hole formed in the flexible region are formed to be perpendicular to the lower copper foil layer of a double-sided FCCL.

As shown in FIG. 8A, a double-sided FCCL 310, in which copper foil layers 314 are respectively formed on two sides of a polyimide film 312, is provided, and, as shown in FIG. 8B, predetermined inner circuit patterns 316 are formed using the copper foil layers 314.

As shown in FIG. 8C, a base substrate 330 is formed by layering coverlays 320 over all of two sides of the double-sided FCCL 310 on which the inner circuit patterns 316 are formed.

As shown in FIG. 8D, after the base substrate 330 is formed, insulation layers 332 and 334 are respectively layered on the portions of coverlays 320 which are to be a rigid region of the base substrate 330, and copper foil layers 336 and 338, having the size corresponding to that of the base substrate 330, are respectively layered on the insulation layers 332 and 334, thereby forming a laminated body 340.

Here, a prepreg, which is a mixed material of reinforcing base material and resin and is cured after it has been heated and pressurized in a semi-cured state, may be used as each of the insulation layers 332 and 334.

As shown in FIG. 8E, the copper foil layers 336 and 338 in the flexible region are etched and thus removed.

As shown in FIG. 8F, a blind via hole 346 is formed in the portion of rigid region using an ultraviolet laser, and a blind via hole 348 and an inner via hole 350 are simultaneously formed in the portions of the flexible region using the ultraviolet laser.

As shown in FIG. 8G, an entire plating layer 360 is formed by plating the entire surface of the laminated body 340 using copper, and, as shown in FIG. 8H, outer circuit patterns 370 are formed in the rigid region using the plating layer 360, and outer circuit patterns 370 including plating layers 374 for the via holes 348 and 350 and additional plating portions 372 adjacent thereto are formed in the flexible region.

That is, the additional plating portions 372 and the via holes 348 and 350 are formed by removing the remainder of the plating layer on the coverlays 320 other than the plating layer adjacent to the via holes 348 and 350 using the method of partially removing the plating layer 360 plated in the flexible region.

Here, the diameters of the additional plating portions 372 are smaller than the diameters of the via holes 348 or 350.

As shown in FIG. 8I, solder resists 380 are formed in the rigid region to expose portions of the outer circuit patterns 370, and thus the rigid-flexible printed circuit board 400 is completed.

Here, if necessary, the ground shield layers may be applied or not applied.

Accordingly, the coverlays are layered on the entire surface of the double-sided FCCL without previous processing thereof, the via holes are formed in the coverlays while a drilling process is performed to form the via holes, and then the copper plating is entirely performed, thereby eliminating the cost of previously processing the coverlays, easily performing a process of provisionally layering the coverlays on the double-sided FCCL, and decreasing the cost therefor.

According to the rigid-flexible printed circuit board of the present invention, since the coverlays are layered on the entire surface of the double-sided FCCL without previous processing thereof, the via holes are formed in the coverlays while a drilling process is performed to form the via holes, and then the copper plating is entirely performed, it is possible to decrease the cost of previously processing the coverlays, easily perform a process of provisionally layering the coverlays on the double-sided FCCL, and decrease the cost therefor.

Further, since the plating layer is formed in the flexible region, it is possible to decrease the cost of applying and removing the resists and prevent defective products from occurring because residual resist does not remain after removal of the resist.

Claims

1. A rigid-flexible printed circuit board comprising a rigid region and a flexible region, wherein the flexible region comprises: at least one double-sided flexible copper foil laminate;coverlays respectively layered on copper foil layers of the flexible copper foil laminate, and provided with windows having predetermined diameters; andplating layers respectively formed in the windows, the plating layers comprising additional plating portions that have diameters respectively larger than predetermined diameters of the windows and are formed on portions of the coverlays adjacent to the windows.
2. The rigid-flexible printed circuit board as set forth in claim 1, wherein a blind via hole having a diameter smaller than the predetermined diameter of each of the windows is formed in the flexible region to correspond to each of the windows.
3. The rigid-flexible printed circuit board as set forth in claim 1, wherein an inner via hole which has a diameter smaller than the predetermined diameter of each of the windows, and through which the upper and lower portions of the flexible copper foil laminate are electrically connected, is formed in the flexible region to correspond to each of the windows.
4. The rigid-flexible printed circuit board as set forth in claim 1, wherein the least one flexible copper foil laminate is at least two flexible copper coil laminates layered in the flexible region, and the windows are formed in outermost copper foil layers of the layered flexible copper foil laminates.
5. A method of manufacturing a rigid-flexible printed circuit board, comprising the steps of: (A) providing a base substrate in which coverlays are respectively formed on two sides of a flexible copper foil laminate on both sides of which inner circuit patterns are respectively formed;(B) layering insulation layers and copper foil layers on portions of coverlays which are to be a rigid region of the flexible copper foil laminate;(C) forming a via hole in the rigid region, and, simultaneously, forming first windows in the coverlays in a flexible region;(D) forming outer circuit patterns including areas adjacent to the first windows; and(E) applying solder resist in the rigid region to expose portions of the external circuit patterns;wherein the outer circuit patterns formed in the areas adjacent to the first windows include additional plating portions for covering portions of the coverlays.
6. The method as set forth in claim 5, wherein, at step (C), the via hole formed in the rigid region and the first windows formed in the flexible region are formed using a CO2 laser.
7. The method as set forth in claim 5, after step (B), further comprising the steps of: (B-1) forming a through hole in the rigid region through a drilling process; and(B-2) forming a second window in a copper foil in the rigid region.
8. The method as set forth in claim 7, wherein a via hole is formed in the rigid region to correspond to the second window.
9. The method as set forth in claim 5, after step (E), further comprising: (E-1) applying conductive paste to form ground shield layers on outer sides of the flexible region.
10. A method of manufacturing a rigid-flexible printed circuit board, comprising the steps of: (A) providing a base substrate in which coverlays are respectively formed on two sides of a flexible copper foil laminate on both sides of which inner circuit patterns and a first window are respectively formed;(B) layering insulation layers and copper foil layers on portions of coverlays which are to be a rigid region of the base substrate;(C) forming a via hole in the rigid region, and, simultaneously, forming a via hole to correspond to the first window in a flexible region;(D) forming outer circuit patterns including areas adjacent to the first window; and(E) applying solder resists in the rigid region to expose portions of external circuit patterns,wherein the region adjacent to the via holes in the flexible region includes additional plating portions for covering the coverlays.
11. The method as set forth in claim 10, wherein, at step (C), the via hole formed in the rigid region and the via hole formed in the flexible region are formed using a CO2 laser.
12. The method as set forth in claim 10, wherein diameters of the additional plating portions are larger than distances between the coverlays corresponding to the additional plating layers, and the distances between the coverlays are larger than a diameter of the first window.
13. The method as set forth in claim 10, wherein the via hole formed in the flexible region is a blind via hole.
14. The method as set forth in claim 10, wherein the via hole formed in the flexible region is an inner via hole.
15. The method as set forth in claim 10, further comprising, after the step (B): (B-1) forming a second window in a copper foil in the rigid region.
16. The method as set forth in claim 15, wherein a via hole is formed in the rigid region to correspond to the second window.
17. A method of manufacturing a rigid-flexible printed circuit board, comprising the steps of: (A) providing a base substrate in which coverlays are respectively formed on two sides of a flexible copper foil laminate, on both sides of which inner circuit patterns are respectively formed;(B) layering insulation layers and copper foil layers on the portions of coverlays which are to be a rigid region of the flexible copper foil laminate;(C) forming a via hole in the rigid region, and simultaneously forming a via hole in one spot of a flexible region;(D) forming outer circuit patterns including areas adjacent to a via hole window; and(E) applying solder resists in the rigid region to expose portions of the external circuit patterns,wherein the region adjacent to the via holes in the flexible region includes additional plating portions for covering the coverlays.
18. The method as set forth in claim 17, wherein, at the step (C), the via hole formed in the rigid region and the via hole formed in the flexible region are formed using an ultraviolet laser.
19. The method as set forth in claim 17, wherein, at the step (C), the via hole formed in the flexible region is a blind via hole.
20. The method as set forth in claim 17, wherein, at the step (C), the via hole formed in the flexible region is an inner via hole.

Priority Claims (1)

Number	Date	Country	Kind
10-2006-0065847	Jul 2006	KR	national

Rigid-flexible printed circuit board and method of manufacturing the same

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CPC

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Abstract

Description

Claims

Priority Claims (1)